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fix(shared): exclude server runtimes from the worker navigator fallback#8840

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Merged
jacekradko merged 3 commits into from
Jun 12, 2026
Merged

fix(shared): exclude server runtimes from the worker navigator fallback #8840

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fd2dfcc
fix(shared): exclude server runtimes from the worker navigator fallback
jacekradko Jun 12, 2026
fe6f0af
Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes
jacekradko Jun 12, 2026
d20b15b
Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes
jacekradko Jun 12, 2026
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5 changes: 5 additions & 0 deletions .changeset/shared-worker-navigator-server-runtimes.md
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
---
'@clerk/shared': patch
---

Exclude self-identified server runtimes (`Cloudflare-Workers`, `Node.js`, `Deno`, `Bun` user agents) from the worker-scope `navigator` fallback used by `isValidBrowser`, `isBrowserOnline`, and `isValidBrowserOnline`. Today Cloudflare's workerd is excluded only because its `self` does not satisfy `instanceof WorkerGlobalScope`; this guard keeps the checks returning `false` on server-side worker runtimes even if that implementation detail changes, while real browser web/service workers (such as MV3 extension background workers) are unaffected.
47 changes: 47 additions & 0 deletions packages/shared/src/__tests__/browser.spec.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -77,6 +77,42 @@ describe('isValidBrowser', () => {
expect(isValidBrowser()).toBe(true);
});

it('returns false in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
// Today workerd's `self` fails the `instanceof WorkerGlobalScope` gate, but that is a
// quirk of its prototype chain. This simulates a spec-compliant workerd: full worker
// scope, navigator present, but the user agent self-identifies as a server runtime.
mockServiceWorkerScope();
userAgentGetter.mockReturnValue('Cloudflare-Workers');
webdriverGetter.mockReturnValue(false);

expect(isValidBrowser()).toBe(false);
});

it.each(['Node.js/24', 'Deno/2.5.0', 'Bun/1.3.9'])(
'returns false in a worker scope whose navigator identifies the %s server runtime',
userAgent => {
mockServiceWorkerScope();
userAgentGetter.mockReturnValue(userAgent);
webdriverGetter.mockReturnValue(false);

expect(isValidBrowser()).toBe(false);
},
);

it('returns false when WorkerGlobalScope exists but self is not an instance of it (e.g. workerd today)', () => {
// workerd exposes the WorkerGlobalScope constructor without linking `self` to its
// prototype chain, so the instanceof gate must reject it even with a browser-like UA.
vi.stubGlobal('WorkerGlobalScope', class {});
vi.stubGlobal('self', {
navigator: { userAgent: 'Mozilla/5.0 Chrome/120.0.0.0 Safari/537.36', onLine: true, webdriver: false },
});
const windowSpy = vi.spyOn(global, 'window', 'get');
// @ts-ignore - Test
windowSpy.mockReturnValue(undefined);

expect(isValidBrowser()).toBe(false);
});

it('returns true if in browser, navigator is not a bot, and webdriver is not enabled', () => {
userAgentGetter.mockReturnValue(
'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0',
Expand DownExpand Up@@ -275,4 +311,15 @@ describe('isValidBrowserOnline', () => {

expect(isValidBrowserOnline()).toBe(false);
});

it('returns FALSE in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
// Cloudflare Workers do not implement `navigator.onLine`, so without the server-runtime
// exclusion this would fall into the "onLine is not a boolean -> assume online" branch.
mockServiceWorkerScope();
userAgentGetter.mockReturnValue('Cloudflare-Workers');
webdriverGetter.mockReturnValue(false);
onLineGetter.mockReturnValue(undefined);

expect(isValidBrowserOnline()).toBe(false);
});
});
14 changes: 13 additions & 1 deletion packages/shared/src/browser.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -49,6 +49,17 @@ export function userAgentIsRobot(userAgent: string): boolean {
return !userAgent ? false : botAgentRegex.test(userAgent);
}

/**
* Server-side runtimes with worker-like globals self-identify in `navigator.userAgent`
* (`Cloudflare-Workers`, `Node.js/24`, `Deno/2.5.0`, `Bun/1.3.9`). Today workerd's `self`
* does not satisfy `instanceof WorkerGlobalScope` (even though it exposes the constructor),
* so the scope gate alone happens to exclude it, but that is an implementation detail of
* workerd's prototype chain, not a guarantee. Excluding self-identified server runtimes by
* user agent keeps these heuristics server-false even if such a runtime becomes fully
* spec-compliant about its worker scope.
*/
const serverRuntimeUserAgentRegex = /^(Cloudflare-Workers|Node\.js|Deno|Bun)\b/i;

/**
* Resolves the `Navigator` object from either the DOM `window` (standard browsers)
* or a Web/Service Worker global scope. An MV3 extension background service worker
Expand All@@ -74,7 +85,8 @@ function getNavigator(): Navigator | null {
if (
typeof workerScope.WorkerGlobalScope === 'function' &&
workerScope.self instanceof workerScope.WorkerGlobalScope &&
workerScope.self.navigator
workerScope.self.navigator &&
!serverRuntimeUserAgentRegex.test(workerScope.self.navigator.userAgent ?? '')
) {
return workerScope.self.navigator;
}
Expand Down
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
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;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
fix(shared): exclude server runtimes from the worker navigator fallback by jacekradko · Pull Request #8840 · clerk/javascript · GitHub
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fix(shared): exclude server runtimes from the worker navigator fallback#8840

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 Merged

jacekradko
merged 3 commits into

from

Jun 12, 2026
 Merged


fix(shared): exclude server runtimes from the worker navigator fallback
#8840
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fd2dfcc

fix(shared): exclude server runtimes from the worker navigator fallback


jacekradko Jun 12, 2026
fe6f0af

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026
d20b15b

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026

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5 changes: 5 additions & 0 deletions
.changeset/shared-worker-navigator-server-runtimes.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
---
'@clerk/shared': patch
---

Exclude self-identified server runtimes (`Cloudflare-Workers`, `Node.js`, `Deno`, `Bun` user agents) from the worker-scope `navigator` fallback used by `isValidBrowser`, `isBrowserOnline`, and `isValidBrowserOnline`. Today Cloudflare's workerd is excluded only because its `self` does not satisfy `instanceof WorkerGlobalScope`; this guard keeps the checks returning `false` on server-side worker runtimes even if that implementation detail changes, while real browser web/service workers (such as MV3 extension background workers) are unaffected.

47 changes: 47 additions & 0 deletions
packages/shared/src/__tests__/browser.spec.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -77,6 +77,42 @@ describe('isValidBrowser', () => {
 expect(isValidBrowser()).toBe(true);
 });

 it('returns false in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Today workerd's `self` fails the `instanceof WorkerGlobalScope` gate, but that is a
 // quirk of its prototype chain. This simulates a spec-compliant workerd: full worker
 // scope, navigator present, but the user agent self-identifies as a server runtime.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 });

 it.each(['Node.js/24', 'Deno/2.5.0', 'Bun/1.3.9'])(
 'returns false in a worker scope whose navigator identifies the %s server runtime',
 userAgent => {
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue(userAgent);
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 },
 );

 it('returns false when WorkerGlobalScope exists but self is not an instance of it (e.g. workerd today)', () => {
 // workerd exposes the WorkerGlobalScope constructor without linking `self` to its
 // prototype chain, so the instanceof gate must reject it even with a browser-like UA.
 vi.stubGlobal('WorkerGlobalScope', class {});
 vi.stubGlobal('self', {
 navigator: { userAgent: 'Mozilla/5.0 Chrome/120.0.0.0 Safari/537.36', onLine: true, webdriver: false },
 });
 const windowSpy = vi.spyOn(global, 'window', 'get');
 // @ts-ignore - Test
 windowSpy.mockReturnValue(undefined);

 expect(isValidBrowser()).toBe(false);
 });

 it('returns true if in browser, navigator is not a bot, and webdriver is not enabled', () => {
 userAgentGetter.mockReturnValue(
 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0',
Expand DownExpand Up@@ -275,4 +311,15 @@ describe('isValidBrowserOnline', () => {

 expect(isValidBrowserOnline()).toBe(false);
 });

 it('returns FALSE in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Cloudflare Workers do not implement `navigator.onLine`, so without the server-runtime
 // exclusion this would fall into the "onLine is not a boolean -> assume online" branch.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);
 onLineGetter.mockReturnValue(undefined);

 expect(isValidBrowserOnline()).toBe(false);
 });
});

14 changes: 13 additions & 1 deletion
packages/shared/src/browser.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -49,6 +49,17 @@ export function userAgentIsRobot(userAgent: string): boolean {
 return !userAgent ? false : botAgentRegex.test(userAgent);
}

/**
 * Server-side runtimes with worker-like globals self-identify in `navigator.userAgent`
 * (`Cloudflare-Workers`, `Node.js/24`, `Deno/2.5.0`, `Bun/1.3.9`). Today workerd's `self`
 * does not satisfy `instanceof WorkerGlobalScope` (even though it exposes the constructor),
 * so the scope gate alone happens to exclude it, but that is an implementation detail of
 * workerd's prototype chain, not a guarantee. Excluding self-identified server runtimes by
 * user agent keeps these heuristics server-false even if such a runtime becomes fully
 * spec-compliant about its worker scope.
 */
const serverRuntimeUserAgentRegex = /^(Cloudflare-Workers|Node\.js|Deno|Bun)\b/i;

/**
 * Resolves the `Navigator` object from either the DOM `window` (standard browsers)
 * or a Web/Service Worker global scope. An MV3 extension background service worker
Expand All@@ -74,7 +85,8 @@ function getNavigator(): Navigator | null {
 if (
 typeof workerScope.WorkerGlobalScope === 'function' &&
 workerScope.self instanceof workerScope.WorkerGlobalScope &&
 workerScope.self.navigator
 workerScope.self.navigator &&
 !serverRuntimeUserAgentRegex.test(workerScope.self.navigator.userAgent ?? '')
 ) {
 return workerScope.self.navigator;
 }
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
fix(shared): exclude server runtimes from the worker navigator fallback by jacekradko · Pull Request #8840 · clerk/javascript · GitHub
Skip to content
fix(shared): exclude server runtimes from the worker navigator fallback#8840

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Sign in
to your account

 Merged

jacekradko
merged 3 commits into

from

Jun 12, 2026
 Merged


fix(shared): exclude server runtimes from the worker navigator fallback
#8840
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fd2dfcc

fix(shared): exclude server runtimes from the worker navigator fallback


jacekradko Jun 12, 2026
fe6f0af

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026
d20b15b

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026

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5 changes: 5 additions & 0 deletions
.changeset/shared-worker-navigator-server-runtimes.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
---
'@clerk/shared': patch
---

Exclude self-identified server runtimes (`Cloudflare-Workers`, `Node.js`, `Deno`, `Bun` user agents) from the worker-scope `navigator` fallback used by `isValidBrowser`, `isBrowserOnline`, and `isValidBrowserOnline`. Today Cloudflare's workerd is excluded only because its `self` does not satisfy `instanceof WorkerGlobalScope`; this guard keeps the checks returning `false` on server-side worker runtimes even if that implementation detail changes, while real browser web/service workers (such as MV3 extension background workers) are unaffected.

47 changes: 47 additions & 0 deletions
packages/shared/src/__tests__/browser.spec.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -77,6 +77,42 @@ describe('isValidBrowser', () => {
 expect(isValidBrowser()).toBe(true);
 });

 it('returns false in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Today workerd's `self` fails the `instanceof WorkerGlobalScope` gate, but that is a
 // quirk of its prototype chain. This simulates a spec-compliant workerd: full worker
 // scope, navigator present, but the user agent self-identifies as a server runtime.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 });

 it.each(['Node.js/24', 'Deno/2.5.0', 'Bun/1.3.9'])(
 'returns false in a worker scope whose navigator identifies the %s server runtime',
 userAgent => {
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue(userAgent);
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 },
 );

 it('returns false when WorkerGlobalScope exists but self is not an instance of it (e.g. workerd today)', () => {
 // workerd exposes the WorkerGlobalScope constructor without linking `self` to its
 // prototype chain, so the instanceof gate must reject it even with a browser-like UA.
 vi.stubGlobal('WorkerGlobalScope', class {});
 vi.stubGlobal('self', {
 navigator: { userAgent: 'Mozilla/5.0 Chrome/120.0.0.0 Safari/537.36', onLine: true, webdriver: false },
 });
 const windowSpy = vi.spyOn(global, 'window', 'get');
 // @ts-ignore - Test
 windowSpy.mockReturnValue(undefined);

 expect(isValidBrowser()).toBe(false);
 });

 it('returns true if in browser, navigator is not a bot, and webdriver is not enabled', () => {
 userAgentGetter.mockReturnValue(
 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0',
Expand DownExpand Up@@ -275,4 +311,15 @@ describe('isValidBrowserOnline', () => {

 expect(isValidBrowserOnline()).toBe(false);
 });

 it('returns FALSE in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Cloudflare Workers do not implement `navigator.onLine`, so without the server-runtime
 // exclusion this would fall into the "onLine is not a boolean -> assume online" branch.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);
 onLineGetter.mockReturnValue(undefined);

 expect(isValidBrowserOnline()).toBe(false);
 });
});

14 changes: 13 additions & 1 deletion
packages/shared/src/browser.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -49,6 +49,17 @@ export function userAgentIsRobot(userAgent: string): boolean {
 return !userAgent ? false : botAgentRegex.test(userAgent);
}

/**
 * Server-side runtimes with worker-like globals self-identify in `navigator.userAgent`
 * (`Cloudflare-Workers`, `Node.js/24`, `Deno/2.5.0`, `Bun/1.3.9`). Today workerd's `self`
 * does not satisfy `instanceof WorkerGlobalScope` (even though it exposes the constructor),
 * so the scope gate alone happens to exclude it, but that is an implementation detail of
 * workerd's prototype chain, not a guarantee. Excluding self-identified server runtimes by
 * user agent keeps these heuristics server-false even if such a runtime becomes fully
 * spec-compliant about its worker scope.
 */
const serverRuntimeUserAgentRegex = /^(Cloudflare-Workers|Node\.js|Deno|Bun)\b/i;

/**
 * Resolves the `Navigator` object from either the DOM `window` (standard browsers)
 * or a Web/Service Worker global scope. An MV3 extension background service worker
Expand All@@ -74,7 +85,8 @@ function getNavigator(): Navigator | null {
 if (
 typeof workerScope.WorkerGlobalScope === 'function' &&
 workerScope.self instanceof workerScope.WorkerGlobalScope &&
 workerScope.self.navigator
 workerScope.self.navigator &&
 !serverRuntimeUserAgentRegex.test(workerScope.self.navigator.userAgent ?? '')
 ) {
 return workerScope.self.navigator;
 }
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
fix(shared): exclude server runtimes from the worker navigator fallback by jacekradko · Pull Request #8840 · clerk/javascript · GitHub
Skip to content
fix(shared): exclude server runtimes from the worker navigator fallback#8840

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 Merged

jacekradko
merged 3 commits into

from

Jun 12, 2026
 Merged


fix(shared): exclude server runtimes from the worker navigator fallback
#8840
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fd2dfcc

fix(shared): exclude server runtimes from the worker navigator fallback


jacekradko Jun 12, 2026
fe6f0af

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026
d20b15b

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026

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5 changes: 5 additions & 0 deletions
.changeset/shared-worker-navigator-server-runtimes.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
---
'@clerk/shared': patch
---

Exclude self-identified server runtimes (`Cloudflare-Workers`, `Node.js`, `Deno`, `Bun` user agents) from the worker-scope `navigator` fallback used by `isValidBrowser`, `isBrowserOnline`, and `isValidBrowserOnline`. Today Cloudflare's workerd is excluded only because its `self` does not satisfy `instanceof WorkerGlobalScope`; this guard keeps the checks returning `false` on server-side worker runtimes even if that implementation detail changes, while real browser web/service workers (such as MV3 extension background workers) are unaffected.

47 changes: 47 additions & 0 deletions
packages/shared/src/__tests__/browser.spec.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -77,6 +77,42 @@ describe('isValidBrowser', () => {
 expect(isValidBrowser()).toBe(true);
 });

 it('returns false in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Today workerd's `self` fails the `instanceof WorkerGlobalScope` gate, but that is a
 // quirk of its prototype chain. This simulates a spec-compliant workerd: full worker
 // scope, navigator present, but the user agent self-identifies as a server runtime.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 });

 it.each(['Node.js/24', 'Deno/2.5.0', 'Bun/1.3.9'])(
 'returns false in a worker scope whose navigator identifies the %s server runtime',
 userAgent => {
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue(userAgent);
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 },
 );

 it('returns false when WorkerGlobalScope exists but self is not an instance of it (e.g. workerd today)', () => {
 // workerd exposes the WorkerGlobalScope constructor without linking `self` to its
 // prototype chain, so the instanceof gate must reject it even with a browser-like UA.
 vi.stubGlobal('WorkerGlobalScope', class {});
 vi.stubGlobal('self', {
 navigator: { userAgent: 'Mozilla/5.0 Chrome/120.0.0.0 Safari/537.36', onLine: true, webdriver: false },
 });
 const windowSpy = vi.spyOn(global, 'window', 'get');
 // @ts-ignore - Test
 windowSpy.mockReturnValue(undefined);

 expect(isValidBrowser()).toBe(false);
 });

 it('returns true if in browser, navigator is not a bot, and webdriver is not enabled', () => {
 userAgentGetter.mockReturnValue(
 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0',
Expand DownExpand Up@@ -275,4 +311,15 @@ describe('isValidBrowserOnline', () => {

 expect(isValidBrowserOnline()).toBe(false);
 });

 it('returns FALSE in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Cloudflare Workers do not implement `navigator.onLine`, so without the server-runtime
 // exclusion this would fall into the "onLine is not a boolean -> assume online" branch.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);
 onLineGetter.mockReturnValue(undefined);

 expect(isValidBrowserOnline()).toBe(false);
 });
});

14 changes: 13 additions & 1 deletion
packages/shared/src/browser.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -49,6 +49,17 @@ export function userAgentIsRobot(userAgent: string): boolean {
 return !userAgent ? false : botAgentRegex.test(userAgent);
}

/**
 * Server-side runtimes with worker-like globals self-identify in `navigator.userAgent`
 * (`Cloudflare-Workers`, `Node.js/24`, `Deno/2.5.0`, `Bun/1.3.9`). Today workerd's `self`
 * does not satisfy `instanceof WorkerGlobalScope` (even though it exposes the constructor),
 * so the scope gate alone happens to exclude it, but that is an implementation detail of
 * workerd's prototype chain, not a guarantee. Excluding self-identified server runtimes by
 * user agent keeps these heuristics server-false even if such a runtime becomes fully
 * spec-compliant about its worker scope.
 */
const serverRuntimeUserAgentRegex = /^(Cloudflare-Workers|Node\.js|Deno|Bun)\b/i;

/**
 * Resolves the `Navigator` object from either the DOM `window` (standard browsers)
 * or a Web/Service Worker global scope. An MV3 extension background service worker
Expand All@@ -74,7 +85,8 @@ function getNavigator(): Navigator | null {
 if (
 typeof workerScope.WorkerGlobalScope === 'function' &&
 workerScope.self instanceof workerScope.WorkerGlobalScope &&
 workerScope.self.navigator
 workerScope.self.navigator &&
 !serverRuntimeUserAgentRegex.test(workerScope.self.navigator.userAgent ?? '')
 ) {
 return workerScope.self.navigator;
 }
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
fix(shared): exclude server runtimes from the worker navigator fallback by jacekradko · Pull Request #8840 · clerk/javascript · GitHub
Skip to content
fix(shared): exclude server runtimes from the worker navigator fallback#8840

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 Merged

jacekradko
merged 3 commits into

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Jun 12, 2026
 Merged


fix(shared): exclude server runtimes from the worker navigator fallback
#8840
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fd2dfcc

fix(shared): exclude server runtimes from the worker navigator fallback


jacekradko Jun 12, 2026
fe6f0af

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026
d20b15b

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026

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5 changes: 5 additions & 0 deletions
.changeset/shared-worker-navigator-server-runtimes.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
---
'@clerk/shared': patch
---

Exclude self-identified server runtimes (`Cloudflare-Workers`, `Node.js`, `Deno`, `Bun` user agents) from the worker-scope `navigator` fallback used by `isValidBrowser`, `isBrowserOnline`, and `isValidBrowserOnline`. Today Cloudflare's workerd is excluded only because its `self` does not satisfy `instanceof WorkerGlobalScope`; this guard keeps the checks returning `false` on server-side worker runtimes even if that implementation detail changes, while real browser web/service workers (such as MV3 extension background workers) are unaffected.

47 changes: 47 additions & 0 deletions
packages/shared/src/__tests__/browser.spec.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -77,6 +77,42 @@ describe('isValidBrowser', () => {
 expect(isValidBrowser()).toBe(true);
 });

 it('returns false in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Today workerd's `self` fails the `instanceof WorkerGlobalScope` gate, but that is a
 // quirk of its prototype chain. This simulates a spec-compliant workerd: full worker
 // scope, navigator present, but the user agent self-identifies as a server runtime.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 });

 it.each(['Node.js/24', 'Deno/2.5.0', 'Bun/1.3.9'])(
 'returns false in a worker scope whose navigator identifies the %s server runtime',
 userAgent => {
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue(userAgent);
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 },
 );

 it('returns false when WorkerGlobalScope exists but self is not an instance of it (e.g. workerd today)', () => {
 // workerd exposes the WorkerGlobalScope constructor without linking `self` to its
 // prototype chain, so the instanceof gate must reject it even with a browser-like UA.
 vi.stubGlobal('WorkerGlobalScope', class {});
 vi.stubGlobal('self', {
 navigator: { userAgent: 'Mozilla/5.0 Chrome/120.0.0.0 Safari/537.36', onLine: true, webdriver: false },
 });
 const windowSpy = vi.spyOn(global, 'window', 'get');
 // @ts-ignore - Test
 windowSpy.mockReturnValue(undefined);

 expect(isValidBrowser()).toBe(false);
 });

 it('returns true if in browser, navigator is not a bot, and webdriver is not enabled', () => {
 userAgentGetter.mockReturnValue(
 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0',
Expand DownExpand Up@@ -275,4 +311,15 @@ describe('isValidBrowserOnline', () => {

 expect(isValidBrowserOnline()).toBe(false);
 });

 it('returns FALSE in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Cloudflare Workers do not implement `navigator.onLine`, so without the server-runtime
 // exclusion this would fall into the "onLine is not a boolean -> assume online" branch.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);
 onLineGetter.mockReturnValue(undefined);

 expect(isValidBrowserOnline()).toBe(false);
 });
});

14 changes: 13 additions & 1 deletion
packages/shared/src/browser.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -49,6 +49,17 @@ export function userAgentIsRobot(userAgent: string): boolean {
 return !userAgent ? false : botAgentRegex.test(userAgent);
}

/**
 * Server-side runtimes with worker-like globals self-identify in `navigator.userAgent`
 * (`Cloudflare-Workers`, `Node.js/24`, `Deno/2.5.0`, `Bun/1.3.9`). Today workerd's `self`
 * does not satisfy `instanceof WorkerGlobalScope` (even though it exposes the constructor),
 * so the scope gate alone happens to exclude it, but that is an implementation detail of
 * workerd's prototype chain, not a guarantee. Excluding self-identified server runtimes by
 * user agent keeps these heuristics server-false even if such a runtime becomes fully
 * spec-compliant about its worker scope.
 */
const serverRuntimeUserAgentRegex = /^(Cloudflare-Workers|Node\.js|Deno|Bun)\b/i;

/**
 * Resolves the `Navigator` object from either the DOM `window` (standard browsers)
 * or a Web/Service Worker global scope. An MV3 extension background service worker
Expand All@@ -74,7 +85,8 @@ function getNavigator(): Navigator | null {
 if (
 typeof workerScope.WorkerGlobalScope === 'function' &&
 workerScope.self instanceof workerScope.WorkerGlobalScope &&
 workerScope.self.navigator
 workerScope.self.navigator &&
 !serverRuntimeUserAgentRegex.test(workerScope.self.navigator.userAgent ?? '')
 ) {
 return workerScope.self.navigator;
 }
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
fix(shared): exclude server runtimes from the worker navigator fallback by jacekradko · Pull Request #8840 · clerk/javascript · GitHub
Skip to content
fix(shared): exclude server runtimes from the worker navigator fallback#8840

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to your account

 Merged

jacekradko
merged 3 commits into

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Jun 12, 2026
 Merged


fix(shared): exclude server runtimes from the worker navigator fallback
#8840
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fd2dfcc

fix(shared): exclude server runtimes from the worker navigator fallback


jacekradko Jun 12, 2026
fe6f0af

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026
d20b15b

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026

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5 changes: 5 additions & 0 deletions
.changeset/shared-worker-navigator-server-runtimes.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
---
'@clerk/shared': patch
---

Exclude self-identified server runtimes (`Cloudflare-Workers`, `Node.js`, `Deno`, `Bun` user agents) from the worker-scope `navigator` fallback used by `isValidBrowser`, `isBrowserOnline`, and `isValidBrowserOnline`. Today Cloudflare's workerd is excluded only because its `self` does not satisfy `instanceof WorkerGlobalScope`; this guard keeps the checks returning `false` on server-side worker runtimes even if that implementation detail changes, while real browser web/service workers (such as MV3 extension background workers) are unaffected.

47 changes: 47 additions & 0 deletions
packages/shared/src/__tests__/browser.spec.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -77,6 +77,42 @@ describe('isValidBrowser', () => {
 expect(isValidBrowser()).toBe(true);
 });

 it('returns false in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Today workerd's `self` fails the `instanceof WorkerGlobalScope` gate, but that is a
 // quirk of its prototype chain. This simulates a spec-compliant workerd: full worker
 // scope, navigator present, but the user agent self-identifies as a server runtime.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 });

 it.each(['Node.js/24', 'Deno/2.5.0', 'Bun/1.3.9'])(
 'returns false in a worker scope whose navigator identifies the %s server runtime',
 userAgent => {
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue(userAgent);
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 },
 );

 it('returns false when WorkerGlobalScope exists but self is not an instance of it (e.g. workerd today)', () => {
 // workerd exposes the WorkerGlobalScope constructor without linking `self` to its
 // prototype chain, so the instanceof gate must reject it even with a browser-like UA.
 vi.stubGlobal('WorkerGlobalScope', class {});
 vi.stubGlobal('self', {
 navigator: { userAgent: 'Mozilla/5.0 Chrome/120.0.0.0 Safari/537.36', onLine: true, webdriver: false },
 });
 const windowSpy = vi.spyOn(global, 'window', 'get');
 // @ts-ignore - Test
 windowSpy.mockReturnValue(undefined);

 expect(isValidBrowser()).toBe(false);
 });

 it('returns true if in browser, navigator is not a bot, and webdriver is not enabled', () => {
 userAgentGetter.mockReturnValue(
 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0',
Expand DownExpand Up@@ -275,4 +311,15 @@ describe('isValidBrowserOnline', () => {

 expect(isValidBrowserOnline()).toBe(false);
 });

 it('returns FALSE in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Cloudflare Workers do not implement `navigator.onLine`, so without the server-runtime
 // exclusion this would fall into the "onLine is not a boolean -> assume online" branch.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);
 onLineGetter.mockReturnValue(undefined);

 expect(isValidBrowserOnline()).toBe(false);
 });
});

14 changes: 13 additions & 1 deletion
packages/shared/src/browser.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -49,6 +49,17 @@ export function userAgentIsRobot(userAgent: string): boolean {
 return !userAgent ? false : botAgentRegex.test(userAgent);
}

/**
 * Server-side runtimes with worker-like globals self-identify in `navigator.userAgent`
 * (`Cloudflare-Workers`, `Node.js/24`, `Deno/2.5.0`, `Bun/1.3.9`). Today workerd's `self`
 * does not satisfy `instanceof WorkerGlobalScope` (even though it exposes the constructor),
 * so the scope gate alone happens to exclude it, but that is an implementation detail of
 * workerd's prototype chain, not a guarantee. Excluding self-identified server runtimes by
 * user agent keeps these heuristics server-false even if such a runtime becomes fully
 * spec-compliant about its worker scope.
 */
const serverRuntimeUserAgentRegex = /^(Cloudflare-Workers|Node\.js|Deno|Bun)\b/i;

/**
 * Resolves the `Navigator` object from either the DOM `window` (standard browsers)
 * or a Web/Service Worker global scope. An MV3 extension background service worker
Expand All@@ -74,7 +85,8 @@ function getNavigator(): Navigator | null {
 if (
 typeof workerScope.WorkerGlobalScope === 'function' &&
 workerScope.self instanceof workerScope.WorkerGlobalScope &&
 workerScope.self.navigator
 workerScope.self.navigator &&
 !serverRuntimeUserAgentRegex.test(workerScope.self.navigator.userAgent ?? '')
 ) {
 return workerScope.self.navigator;
 }
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
fix(shared): exclude server runtimes from the worker navigator fallback by jacekradko · Pull Request #8840 · clerk/javascript · GitHub
Skip to content
fix(shared): exclude server runtimes from the worker navigator fallback#8840

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to your account

 Merged

jacekradko
merged 3 commits into

from

Jun 12, 2026
 Merged


fix(shared): exclude server runtimes from the worker navigator fallback
#8840
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fd2dfcc

fix(shared): exclude server runtimes from the worker navigator fallback


jacekradko Jun 12, 2026
fe6f0af

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026
d20b15b

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026

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5 changes: 5 additions & 0 deletions
.changeset/shared-worker-navigator-server-runtimes.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
---
'@clerk/shared': patch
---

Exclude self-identified server runtimes (`Cloudflare-Workers`, `Node.js`, `Deno`, `Bun` user agents) from the worker-scope `navigator` fallback used by `isValidBrowser`, `isBrowserOnline`, and `isValidBrowserOnline`. Today Cloudflare's workerd is excluded only because its `self` does not satisfy `instanceof WorkerGlobalScope`; this guard keeps the checks returning `false` on server-side worker runtimes even if that implementation detail changes, while real browser web/service workers (such as MV3 extension background workers) are unaffected.

47 changes: 47 additions & 0 deletions
packages/shared/src/__tests__/browser.spec.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -77,6 +77,42 @@ describe('isValidBrowser', () => {
 expect(isValidBrowser()).toBe(true);
 });

 it('returns false in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Today workerd's `self` fails the `instanceof WorkerGlobalScope` gate, but that is a
 // quirk of its prototype chain. This simulates a spec-compliant workerd: full worker
 // scope, navigator present, but the user agent self-identifies as a server runtime.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 });

 it.each(['Node.js/24', 'Deno/2.5.0', 'Bun/1.3.9'])(
 'returns false in a worker scope whose navigator identifies the %s server runtime',
 userAgent => {
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue(userAgent);
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 },
 );

 it('returns false when WorkerGlobalScope exists but self is not an instance of it (e.g. workerd today)', () => {
 // workerd exposes the WorkerGlobalScope constructor without linking `self` to its
 // prototype chain, so the instanceof gate must reject it even with a browser-like UA.
 vi.stubGlobal('WorkerGlobalScope', class {});
 vi.stubGlobal('self', {
 navigator: { userAgent: 'Mozilla/5.0 Chrome/120.0.0.0 Safari/537.36', onLine: true, webdriver: false },
 });
 const windowSpy = vi.spyOn(global, 'window', 'get');
 // @ts-ignore - Test
 windowSpy.mockReturnValue(undefined);

 expect(isValidBrowser()).toBe(false);
 });

 it('returns true if in browser, navigator is not a bot, and webdriver is not enabled', () => {
 userAgentGetter.mockReturnValue(
 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0',
Expand DownExpand Up@@ -275,4 +311,15 @@ describe('isValidBrowserOnline', () => {

 expect(isValidBrowserOnline()).toBe(false);
 });

 it('returns FALSE in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Cloudflare Workers do not implement `navigator.onLine`, so without the server-runtime
 // exclusion this would fall into the "onLine is not a boolean -> assume online" branch.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);
 onLineGetter.mockReturnValue(undefined);

 expect(isValidBrowserOnline()).toBe(false);
 });
});

14 changes: 13 additions & 1 deletion
packages/shared/src/browser.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -49,6 +49,17 @@ export function userAgentIsRobot(userAgent: string): boolean {
 return !userAgent ? false : botAgentRegex.test(userAgent);
}

/**
 * Server-side runtimes with worker-like globals self-identify in `navigator.userAgent`
 * (`Cloudflare-Workers`, `Node.js/24`, `Deno/2.5.0`, `Bun/1.3.9`). Today workerd's `self`
 * does not satisfy `instanceof WorkerGlobalScope` (even though it exposes the constructor),
 * so the scope gate alone happens to exclude it, but that is an implementation detail of
 * workerd's prototype chain, not a guarantee. Excluding self-identified server runtimes by
 * user agent keeps these heuristics server-false even if such a runtime becomes fully
 * spec-compliant about its worker scope.
 */
const serverRuntimeUserAgentRegex = /^(Cloudflare-Workers|Node\.js|Deno|Bun)\b/i;

/**
 * Resolves the `Navigator` object from either the DOM `window` (standard browsers)
 * or a Web/Service Worker global scope. An MV3 extension background service worker
Expand All@@ -74,7 +85,8 @@ function getNavigator(): Navigator | null {
 if (
 typeof workerScope.WorkerGlobalScope === 'function' &&
 workerScope.self instanceof workerScope.WorkerGlobalScope &&
 workerScope.self.navigator
 workerScope.self.navigator &&
 !serverRuntimeUserAgentRegex.test(workerScope.self.navigator.userAgent ?? '')
 ) {
 return workerScope.self.navigator;
 }
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
fix(shared): exclude server runtimes from the worker navigator fallback by jacekradko · Pull Request #8840 · clerk/javascript · GitHub
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fix(shared): exclude server runtimes from the worker navigator fallback#8840

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jacekradko
merged 3 commits into

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Jun 12, 2026
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fix(shared): exclude server runtimes from the worker navigator fallback
#8840
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fd2dfcc

fix(shared): exclude server runtimes from the worker navigator fallback


jacekradko Jun 12, 2026
fe6f0af

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026
d20b15b

Merge branch 'main' into jacek/shared-worker-navigator-server-runtimes


jacekradko Jun 12, 2026

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5 changes: 5 additions & 0 deletions
.changeset/shared-worker-navigator-server-runtimes.md

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
---
'@clerk/shared': patch
---

Exclude self-identified server runtimes (`Cloudflare-Workers`, `Node.js`, `Deno`, `Bun` user agents) from the worker-scope `navigator` fallback used by `isValidBrowser`, `isBrowserOnline`, and `isValidBrowserOnline`. Today Cloudflare's workerd is excluded only because its `self` does not satisfy `instanceof WorkerGlobalScope`; this guard keeps the checks returning `false` on server-side worker runtimes even if that implementation detail changes, while real browser web/service workers (such as MV3 extension background workers) are unaffected.

47 changes: 47 additions & 0 deletions
packages/shared/src/__tests__/browser.spec.ts

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Original file line numberDiff line numberDiff line change
Expand Up@@ -77,6 +77,42 @@ describe('isValidBrowser', () => {
 expect(isValidBrowser()).toBe(true);
 });

 it('returns false in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Today workerd's `self` fails the `instanceof WorkerGlobalScope` gate, but that is a
 // quirk of its prototype chain. This simulates a spec-compliant workerd: full worker
 // scope, navigator present, but the user agent self-identifies as a server runtime.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 });

 it.each(['Node.js/24', 'Deno/2.5.0', 'Bun/1.3.9'])(
 'returns false in a worker scope whose navigator identifies the %s server runtime',
 userAgent => {
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue(userAgent);
 webdriverGetter.mockReturnValue(false);

 expect(isValidBrowser()).toBe(false);
 },
 );

 it('returns false when WorkerGlobalScope exists but self is not an instance of it (e.g. workerd today)', () => {
 // workerd exposes the WorkerGlobalScope constructor without linking `self` to its
 // prototype chain, so the instanceof gate must reject it even with a browser-like UA.
 vi.stubGlobal('WorkerGlobalScope', class {});
 vi.stubGlobal('self', {
 navigator: { userAgent: 'Mozilla/5.0 Chrome/120.0.0.0 Safari/537.36', onLine: true, webdriver: false },
 });
 const windowSpy = vi.spyOn(global, 'window', 'get');
 // @ts-ignore - Test
 windowSpy.mockReturnValue(undefined);

 expect(isValidBrowser()).toBe(false);
 });

 it('returns true if in browser, navigator is not a bot, and webdriver is not enabled', () => {
 userAgentGetter.mockReturnValue(
 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/109.0',
Expand DownExpand Up@@ -275,4 +311,15 @@ describe('isValidBrowserOnline', () => {

 expect(isValidBrowserOnline()).toBe(false);
 });

 it('returns FALSE in a worker scope whose navigator identifies a server runtime (e.g. Cloudflare Workers)', () => {
 // Cloudflare Workers do not implement `navigator.onLine`, so without the server-runtime
 // exclusion this would fall into the "onLine is not a boolean -> assume online" branch.
 mockServiceWorkerScope();
 userAgentGetter.mockReturnValue('Cloudflare-Workers');
 webdriverGetter.mockReturnValue(false);
 onLineGetter.mockReturnValue(undefined);

 expect(isValidBrowserOnline()).toBe(false);
 });
});

14 changes: 13 additions & 1 deletion
packages/shared/src/browser.ts

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Original file line numberDiff line numberDiff line change
Expand Up@@ -49,6 +49,17 @@ export function userAgentIsRobot(userAgent: string): boolean {
 return !userAgent ? false : botAgentRegex.test(userAgent);
}

/**
 * Server-side runtimes with worker-like globals self-identify in `navigator.userAgent`
 * (`Cloudflare-Workers`, `Node.js/24`, `Deno/2.5.0`, `Bun/1.3.9`). Today workerd's `self`
 * does not satisfy `instanceof WorkerGlobalScope` (even though it exposes the constructor),
 * so the scope gate alone happens to exclude it, but that is an implementation detail of
 * workerd's prototype chain, not a guarantee. Excluding self-identified server runtimes by
 * user agent keeps these heuristics server-false even if such a runtime becomes fully
 * spec-compliant about its worker scope.
 */
const serverRuntimeUserAgentRegex = /^(Cloudflare-Workers|Node\.js|Deno|Bun)\b/i;

/**
 * Resolves the `Navigator` object from either the DOM `window` (standard browsers)
 * or a Web/Service Worker global scope. An MV3 extension background service worker
Expand All@@ -74,7 +85,8 @@ function getNavigator(): Navigator | null {
 if (
 typeof workerScope.WorkerGlobalScope === 'function' &&
 workerScope.self instanceof workerScope.WorkerGlobalScope &&
 workerScope.self.navigator
 workerScope.self.navigator &&
 !serverRuntimeUserAgentRegex.test(workerScope.self.navigator.userAgent ?? '')
 ) {
 return workerScope.self.navigator;
 }
Expand Down
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