Add credentialless as a recognized boolean attribute for iframes - #36148

Merged
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute
Apr 20, 2026
Merged

Add credentialless as a recognized boolean attribute for iframes#36148
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute

Conversation

@vmx906

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Summary

The credentialless attribute is a boolean HTML attribute for <iframe> elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.

Per the Anonymous iframe spec (WICG):

The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false.

partial interface HTMLIFrameElement {
attribute boolean credentialless; };

Changes:

  • ReactDOMComponent.js: Added to both setProp and diffHydratedGenericElement
  • ReactFizzConfigDOM.js: Added to pushAttribute for server-side rendering
  • ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists

Test plan

  • Added unit test in DOMPropertyOperations-test.js verifying credentialless={true} sets the attribute to '' and credentialless={false} removes it
  • All tests pass in source and www channels (590 tests each)
  • Flow type checking passes (dom-node renderer)
  • Prettier and lint pass

## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
@react-sizebot

react-sizebot commented Mar 26, 2026

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Comparing: 3cb2c42...8709472

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js=612.88 kB612.90 kB+0.01%108.30 kB108.31 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js=678.81 kB678.84 kB=119.26 kB119.27 kB
facebook-www/ReactDOM-prod.classic.js=698.20 kB698.23 kB=122.65 kB122.66 kB
facebook-www/ReactDOM-prod.modern.js=688.52 kB688.54 kB+0.01%121.03 kB121.04 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8709472

mahdirajaee

This comment was marked as spam.

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.

case 'seamless':
case 'itemScope': {
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');

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[1]

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

Comment on lines 2852 to 2853
case 'controls':
case 'default':

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@vmx906 I think you need to add credentialless here as well.

Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?

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Good catch! Updated this missing path and added test

@hoxyq
hoxyq merged commit 306a01b into mainApr 20, 2026
239 checks passed
@hoxyq
hoxyq deleted the feat/add-credentialless-iframe-attribute branch April 20, 2026 17:37
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
hoxyq pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
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@vmx906@react-sizebot@hoxyq@mahdirajaee@suvroallen13-web
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
Skip to content

Add credentialless as a recognized boolean attribute for iframes - #36148

Merged
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute
Apr 20, 2026
Merged

Add credentialless as a recognized boolean attribute for iframes#36148
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute

Conversation

@vmx906

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Contributor

Summary

The credentialless attribute is a boolean HTML attribute for <iframe> elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.

Per the Anonymous iframe spec (WICG):

The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false.

partial interface HTMLIFrameElement {
attribute boolean credentialless; };

Changes:

  • ReactDOMComponent.js: Added to both setProp and diffHydratedGenericElement
  • ReactFizzConfigDOM.js: Added to pushAttribute for server-side rendering
  • ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists

Test plan

  • Added unit test in DOMPropertyOperations-test.js verifying credentialless={true} sets the attribute to '' and credentialless={false} removes it
  • All tests pass in source and www channels (590 tests each)
  • Flow type checking passes (dom-node renderer)
  • Prettier and lint pass

## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
@react-sizebot

react-sizebot commented Mar 26, 2026

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Comparing: 3cb2c42...8709472

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js=612.88 kB612.90 kB+0.01%108.30 kB108.31 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js=678.81 kB678.84 kB=119.26 kB119.27 kB
facebook-www/ReactDOM-prod.classic.js=698.20 kB698.23 kB=122.65 kB122.66 kB
facebook-www/ReactDOM-prod.modern.js=688.52 kB688.54 kB+0.01%121.03 kB121.04 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8709472

mahdirajaee

This comment was marked as spam.

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.

case 'seamless':
case 'itemScope': {
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');

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[1]

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

Comment on lines 2852 to 2853
case 'controls':
case 'default':

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@vmx906 I think you need to add credentialless here as well.

Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?

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Good catch! Updated this missing path and added test

@hoxyq
hoxyq merged commit 306a01b into mainApr 20, 2026
239 checks passed
@hoxyq
hoxyq deleted the feat/add-credentialless-iframe-attribute branch April 20, 2026 17:37
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
hoxyq pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

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5 participants

@vmx906@react-sizebot@hoxyq@mahdirajaee@suvroallen13-web
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix"); } } catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
Skip to content

Add credentialless as a recognized boolean attribute for iframes - #36148

Merged
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute
Apr 20, 2026
Merged

Add credentialless as a recognized boolean attribute for iframes#36148
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute

Conversation

@vmx906

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Contributor

Summary

The credentialless attribute is a boolean HTML attribute for <iframe> elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.

Per the Anonymous iframe spec (WICG):

The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false.

partial interface HTMLIFrameElement {
attribute boolean credentialless; };

Changes:

  • ReactDOMComponent.js: Added to both setProp and diffHydratedGenericElement
  • ReactFizzConfigDOM.js: Added to pushAttribute for server-side rendering
  • ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists

Test plan

  • Added unit test in DOMPropertyOperations-test.js verifying credentialless={true} sets the attribute to '' and credentialless={false} removes it
  • All tests pass in source and www channels (590 tests each)
  • Flow type checking passes (dom-node renderer)
  • Prettier and lint pass

## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
@react-sizebot

react-sizebot commented Mar 26, 2026

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Comparing: 3cb2c42...8709472

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js=612.88 kB612.90 kB+0.01%108.30 kB108.31 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js=678.81 kB678.84 kB=119.26 kB119.27 kB
facebook-www/ReactDOM-prod.classic.js=698.20 kB698.23 kB=122.65 kB122.66 kB
facebook-www/ReactDOM-prod.modern.js=688.52 kB688.54 kB+0.01%121.03 kB121.04 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8709472

mahdirajaee

This comment was marked as spam.

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.

case 'seamless':
case 'itemScope': {
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');

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[1]

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

Comment on lines 2852 to 2853
case 'controls':
case 'default':

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@vmx906 I think you need to add credentialless here as well.

Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?

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Good catch! Updated this missing path and added test

@hoxyq
hoxyq merged commit 306a01b into mainApr 20, 2026
239 checks passed
@hoxyq
hoxyq deleted the feat/add-credentialless-iframe-attribute branch April 20, 2026 17:37
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
hoxyq pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

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Successfully merging this pull request may close these issues.

5 participants

@vmx906@react-sizebot@hoxyq@mahdirajaee@suvroallen13-web
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms"); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
Skip to content

Add credentialless as a recognized boolean attribute for iframes - #36148

Merged
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute
Apr 20, 2026
Merged

Add credentialless as a recognized boolean attribute for iframes#36148
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute

Conversation

@vmx906

Copy link
Copy Markdown
Contributor

Summary

The credentialless attribute is a boolean HTML attribute for <iframe> elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.

Per the Anonymous iframe spec (WICG):

The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false.

partial interface HTMLIFrameElement {
attribute boolean credentialless; };

Changes:

  • ReactDOMComponent.js: Added to both setProp and diffHydratedGenericElement
  • ReactFizzConfigDOM.js: Added to pushAttribute for server-side rendering
  • ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists

Test plan

  • Added unit test in DOMPropertyOperations-test.js verifying credentialless={true} sets the attribute to '' and credentialless={false} removes it
  • All tests pass in source and www channels (590 tests each)
  • Flow type checking passes (dom-node renderer)
  • Prettier and lint pass

## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
@react-sizebot

react-sizebot commented Mar 26, 2026

Copy link
Copy Markdown

Comparing: 3cb2c42...8709472

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js=612.88 kB612.90 kB+0.01%108.30 kB108.31 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js=678.81 kB678.84 kB=119.26 kB119.27 kB
facebook-www/ReactDOM-prod.classic.js=698.20 kB698.23 kB=122.65 kB122.66 kB
facebook-www/ReactDOM-prod.modern.js=688.52 kB688.54 kB+0.01%121.03 kB121.04 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8709472

mahdirajaee

This comment was marked as spam.

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.

case 'seamless':
case 'itemScope': {
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');

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[1]

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

Comment on lines 2852 to 2853
case 'controls':
case 'default':

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@vmx906 I think you need to add credentialless here as well.

Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?

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Good catch! Updated this missing path and added test

@hoxyq
hoxyq merged commit 306a01b into mainApr 20, 2026
239 checks passed
@hoxyq
hoxyq deleted the feat/add-credentialless-iframe-attribute branch April 20, 2026 17:37
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
hoxyq pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
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@vmx906@react-sizebot@hoxyq@mahdirajaee@suvroallen13-web
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links"); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + '
Skip to content

Add credentialless as a recognized boolean attribute for iframes - #36148

Merged
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute
Apr 20, 2026
Merged

Add credentialless as a recognized boolean attribute for iframes#36148
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute

Conversation

@vmx906

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Summary

The credentialless attribute is a boolean HTML attribute for <iframe> elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.

Per the Anonymous iframe spec (WICG):

The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false.

partial interface HTMLIFrameElement {
attribute boolean credentialless; };

Changes:

  • ReactDOMComponent.js: Added to both setProp and diffHydratedGenericElement
  • ReactFizzConfigDOM.js: Added to pushAttribute for server-side rendering
  • ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists

Test plan

  • Added unit test in DOMPropertyOperations-test.js verifying credentialless={true} sets the attribute to '' and credentialless={false} removes it
  • All tests pass in source and www channels (590 tests each)
  • Flow type checking passes (dom-node renderer)
  • Prettier and lint pass

## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
@react-sizebot

react-sizebot commented Mar 26, 2026

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Comparing: 3cb2c42...8709472

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js=612.88 kB612.90 kB+0.01%108.30 kB108.31 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js=678.81 kB678.84 kB=119.26 kB119.27 kB
facebook-www/ReactDOM-prod.classic.js=698.20 kB698.23 kB=122.65 kB122.66 kB
facebook-www/ReactDOM-prod.modern.js=688.52 kB688.54 kB+0.01%121.03 kB121.04 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8709472

mahdirajaee

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await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.

case 'seamless':
case 'itemScope': {
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');

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[1]

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

Comment on lines 2852 to 2853
case 'controls':
case 'default':

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@vmx906 I think you need to add credentialless here as well.

Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?

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Good catch! Updated this missing path and added test

@hoxyq
hoxyq merged commit 306a01b into mainApr 20, 2026
239 checks passed
@hoxyq
hoxyq deleted the feat/add-credentialless-iframe-attribute branch April 20, 2026 17:37
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
hoxyq pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
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@vmx906@react-sizebot@hoxyq@mahdirajaee@suvroallen13-web
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default"); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
Skip to content

Add credentialless as a recognized boolean attribute for iframes - #36148

Merged
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute
Apr 20, 2026
Merged

Add credentialless as a recognized boolean attribute for iframes#36148
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute

Conversation

@vmx906

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Summary

The credentialless attribute is a boolean HTML attribute for <iframe> elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.

Per the Anonymous iframe spec (WICG):

The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false.

partial interface HTMLIFrameElement {
attribute boolean credentialless; };

Changes:

  • ReactDOMComponent.js: Added to both setProp and diffHydratedGenericElement
  • ReactFizzConfigDOM.js: Added to pushAttribute for server-side rendering
  • ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists

Test plan

  • Added unit test in DOMPropertyOperations-test.js verifying credentialless={true} sets the attribute to '' and credentialless={false} removes it
  • All tests pass in source and www channels (590 tests each)
  • Flow type checking passes (dom-node renderer)
  • Prettier and lint pass

## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
@react-sizebot

react-sizebot commented Mar 26, 2026

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Comparing: 3cb2c42...8709472

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js=612.88 kB612.90 kB+0.01%108.30 kB108.31 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js=678.81 kB678.84 kB=119.26 kB119.27 kB
facebook-www/ReactDOM-prod.classic.js=698.20 kB698.23 kB=122.65 kB122.66 kB
facebook-www/ReactDOM-prod.modern.js=688.52 kB688.54 kB+0.01%121.03 kB121.04 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8709472

mahdirajaee

This comment was marked as spam.

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.

case 'seamless':
case 'itemScope': {
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');

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[1]

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

Comment on lines 2852 to 2853
case 'controls':
case 'default':

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@vmx906 I think you need to add credentialless here as well.

Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?

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Good catch! Updated this missing path and added test

@hoxyq
hoxyq merged commit 306a01b into mainApr 20, 2026
239 checks passed
@hoxyq
hoxyq deleted the feat/add-credentialless-iframe-attribute branch April 20, 2026 17:37
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
hoxyq pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
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Successfully merging this pull request may close these issues.

5 participants

@vmx906@react-sizebot@hoxyq@mahdirajaee@suvroallen13-web
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers"); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
Skip to content

Add credentialless as a recognized boolean attribute for iframes - #36148

Merged
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute
Apr 20, 2026
Merged

Add credentialless as a recognized boolean attribute for iframes#36148
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute

Conversation

@vmx906

Copy link
Copy Markdown
Contributor

Summary

The credentialless attribute is a boolean HTML attribute for <iframe> elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.

Per the Anonymous iframe spec (WICG):

The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false.

partial interface HTMLIFrameElement {
attribute boolean credentialless; };

Changes:

  • ReactDOMComponent.js: Added to both setProp and diffHydratedGenericElement
  • ReactFizzConfigDOM.js: Added to pushAttribute for server-side rendering
  • ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists

Test plan

  • Added unit test in DOMPropertyOperations-test.js verifying credentialless={true} sets the attribute to '' and credentialless={false} removes it
  • All tests pass in source and www channels (590 tests each)
  • Flow type checking passes (dom-node renderer)
  • Prettier and lint pass

## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
@react-sizebot

react-sizebot commented Mar 26, 2026

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Comparing: 3cb2c42...8709472

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js=612.88 kB612.90 kB+0.01%108.30 kB108.31 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js=678.81 kB678.84 kB=119.26 kB119.27 kB
facebook-www/ReactDOM-prod.classic.js=698.20 kB698.23 kB=122.65 kB122.66 kB
facebook-www/ReactDOM-prod.modern.js=688.52 kB688.54 kB+0.01%121.03 kB121.04 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8709472

mahdirajaee

This comment was marked as spam.

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

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Collaborator

Choose a reason for hiding this comment

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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.

case 'seamless':
case 'itemScope': {
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');

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[1]

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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ContributorAuthor

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

Comment on lines 2852 to 2853
case 'controls':
case 'default':

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@vmx906 I think you need to add credentialless here as well.

Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?

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Good catch! Updated this missing path and added test

@hoxyq
hoxyq merged commit 306a01b into mainApr 20, 2026
239 checks passed
@hoxyq
hoxyq deleted the feat/add-credentialless-iframe-attribute branch April 20, 2026 17:37
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
hoxyq pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

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@vmx906@react-sizebot@hoxyq@mahdirajaee@suvroallen13-web
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode"); } } catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); } })(); })();
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Add credentialless as a recognized boolean attribute for iframes - #36148

Merged
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute
Apr 20, 2026
Merged

Add credentialless as a recognized boolean attribute for iframes#36148
hoxyq merged 2 commits into
mainfrom
feat/add-credentialless-iframe-attribute

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@vmx906

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Summary

The credentialless attribute is a boolean HTML attribute for <iframe> elements that loads the iframe in a new, ephemeral context without access to the parent's credentials (cookies, client certificates, etc.). This change adds it to all boolean attribute switch/case lists in React DOM so it is properly handled as a boolean (set when true, removed when false) rather than being treated as an unknown string attribute.

Per the Anonymous iframe spec (WICG):

The credentialless attribute enables loading documents hosted by the iframe with a new and ephemeral storage partition. It is a boolean value. The default is false.

partial interface HTMLIFrameElement {
attribute boolean credentialless; };

Changes:

  • ReactDOMComponent.js: Added to both setProp and diffHydratedGenericElement
  • ReactFizzConfigDOM.js: Added to pushAttribute for server-side rendering
  • ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists

Test plan

  • Added unit test in DOMPropertyOperations-test.js verifying credentialless={true} sets the attribute to '' and credentialless={false} removes it
  • All tests pass in source and www channels (590 tests each)
  • Flow type checking passes (dom-node renderer)
  • Prettier and lint pass

## Summary
The `credentialless` attribute is a boolean HTML attribute for `<iframe>` elements
that loads the iframe in a new, ephemeral context without access to the parent's
credentials (cookies, client certificates, etc.). This change adds it to all
boolean attribute switch/case lists in React DOM so it is properly handled as a
boolean (set when true, removed when false) rather than being treated as an
unknown string attribute.
Changes:
- ReactDOMComponent.js: Added to both `setProp` and `diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying `credentialless={true}`
sets the attribute to `''` and `credentialless={false}` removes it
- Added server rendering tests in ReactDOMServerIntegrationAttributes-test.js for
both true and false values
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
@react-sizebot

react-sizebot commented Mar 26, 2026

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Comparing: 3cb2c42...8709472

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name+/-BaseCurrent+/- gzipBase gzipCurrent gzip
oss-stable/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.11%1.88 kB1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js=612.88 kB612.90 kB+0.01%108.30 kB108.31 kB
oss-experimental/react-dom/cjs/react-dom.production.js=6.84 kB6.84 kB+0.05%1.88 kB1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js=678.81 kB678.84 kB=119.26 kB119.27 kB
facebook-www/ReactDOM-prod.classic.js=698.20 kB698.23 kB=122.65 kB122.66 kB
facebook-www/ReactDOM-prod.modern.js=688.52 kB688.54 kB+0.01%121.03 kB121.04 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 8709472

mahdirajaee

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await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@vmx906 I am a bit confused, should this be expect(container.firstChild.getAttribute('credentialless')).toBe('true'); ?

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

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@vmx906 Oh, I see, thanks! We use the presence of the attribute as a source of truth for boolean attributes.

case 'seamless':
case 'itemScope': {
if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');

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[1]

await act(() => {
root.render(<iframe credentialless={true} />);
});
expect(container.firstChild.getAttribute('credentialless')).toBe('');

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@hoxyq I believe react set this to empty string when the prop is bool, see [1]

if (value && typeof value !== 'function' && typeof value !== 'symbol') {
domElement.setAttribute(key, '');
}

Comment on lines 2852 to 2853
case 'controls':
case 'default':

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@vmx906 I think you need to add credentialless here as well.

Can you also add a few test cases to ReactDOMServerIntegrationAttributes-test.js, similarly to what you did in DOMPropertyOperations-test.js?

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Good catch! Updated this missing path and added test

@hoxyq
hoxyq merged commit 306a01b into mainApr 20, 2026
239 checks passed
@hoxyq
hoxyq deleted the feat/add-credentialless-iframe-attribute branch April 20, 2026 17:37
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
github-actionsBot pushed a commit that referenced this pull request Apr 20, 2026
)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](306a01b)
hoxyq pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit that referenced this pull request Apr 21, 2026
…#36322)
## Summary
Follow-up to #36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 25, 2026
…ct#36148)
## Summary
The `credentialless` attribute is a boolean HTML attribute for
`<iframe>` elements that loads the iframe in a new, ephemeral context
without access to the parent's credentials (cookies, client
certificates, etc.). This change adds it to all boolean attribute
switch/case lists in React DOM so it is properly handled as a boolean
(set when true, removed when false) rather than being treated as an
unknown string attribute.
Per the [Anonymous iframe spec
(WICG)](https://wicg.github.io/anonymous-iframe/):
> The credentialless attribute enables loading documents hosted by the
iframe with a new and ephemeral storage partition. It is a boolean
value. The default is false.
```
partial interface HTMLIFrameElement {
attribute boolean credentialless;
};
```
Changes:
- ReactDOMComponent.js: Added to both `setProp` and
`diffHydratedGenericElement`
- ReactFizzConfigDOM.js: Added to `pushAttribute` for server-side
rendering
- ReactDOMUnknownPropertyHook.js: Added to both validation switch/case
lists
## Test plan
- Added unit test in DOMPropertyOperations-test.js verifying
`credentialless={true}` sets the attribute to `''` and
`credentialless={false}` removes it
- All tests pass in source and www channels (590 tests each)
- Flow type checking passes (dom-node renderer)
- Prettier and lint pass
DiffTrain build for [306a01b](react@306a01b)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
github-actionsBot pushed a commit to code/lib-react that referenced this pull request Apr 26, 2026
…react#36322)
## Summary
Follow-up to react#36148 (which added credentialless as a recognized boolean
attribute for iframes). Adds credentialless to possibleStandardNames so
React's dev warning can suggest the correct casing when users write it
as Credentialless (or another incorrect case). Includes an SSR test
asserting the "Did you mean credentialless?" warning fires.
## Test plan
- yarn test ReactDOMComponent passes, including the new should warn
about incorrect casing on the credentialless property (ssr) case
DiffTrain build for [94643c3](react@94643c3)
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment

Labels

Projects

None yet

Development

Successfully merging this pull request may close these issues.

5 participants

@vmx906@react-sizebot@hoxyq@mahdirajaee@suvroallen13-web