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Cancel animation when a custom Timeline is used - #35567

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sebmarkbage merged 1 commit into
react:mainfrom
sebmarkbage:gesturefirefoxbug
Jan 20, 2026
Merged

Cancel animation when a custom Timeline is used#35567
sebmarkbage merged 1 commit into
react:mainfrom
sebmarkbage:gesturefirefoxbug

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@sebmarkbagesebmarkbage commented Jan 20, 2026

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Follow up to #35559.

The clean up function of the custom timeline doesn't necessarily clean up the animation. Just the timeline's internal state.

This affects Firefox which doesn't support ScrollTimeline so uses the polyfill's custom timeline.

@sebmarkbage
Cancel animation when a custom Timeline is used
817bd79
The clean up function of the custom timeline doesn't necessarily clean up
the animation. Just the timeline's internal state.
@sebmarkbage
sebmarkbage merged commit d290875 into react:mainJan 20, 2026
14 of 15 checks passed
@github-actionsgithub-actionsBot added the React Core Team Opened by a member of the React Core Team label Jan 20, 2026
@react-sizebot

react-sizebot commented Jan 20, 2026

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Comparing: d343c39...817bd79

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=608.73 kB608.73 kB=107.65 kB107.65 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=674.61 kB674.66 kB=118.59 kB118.59 kB
facebook-www/ReactDOM-prod.classic.js=694.11 kB694.11 kB=122.02 kB122.02 kB
facebook-www/ReactDOM-prod.modern.js=684.50 kB684.50 kB=120.42 kB120.42 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 817bd79

github-actionsBot pushed a commit that referenced this pull request Jan 20, 2026
@sebmarkbage
Cancel animation when a custom Timeline is used (#35567)
6722cbc
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean
up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the
polyfill's custom timeline.
DiffTrain build for [d290875](d290875)
@nextjs-botnextjs-bot mentioned this pull request Jan 20, 2026
Merged
sebmarkbage pushed a commit to vercel/next.js that referenced this pull request Jan 20, 2026
@nextjs-bot
Upgrade React from41b3e9a6-20260119tod2908752-20260119(#88774)
9e33529
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
@rubennorterubennorte mentioned this pull request Jun 5, 2026
Closed
m-kawafuji pushed a commit to m-kawafuji/next.js that referenced this pull request Aug 8, 2026
@nextjs-bot@m-kawafuji
Upgrade React from41b3e9a6-20260119tod2908752-20260119(vercel…
b19ed31
…#88774)
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
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@sebmarkbage@react-sizebot
, '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" + '
Cancel animation when a custom Timeline is used by sebmarkbage · Pull Request #35567 · react/react · GitHub
Skip to content
Cancel animation when a custom Timeline is used - #35567
Merged
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Jan 20, 2026
Merged
Cancel animation when a custom Timeline is used#35567
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Conversation
@sebmarkbage
@sebmarkbagesebmarkbage
commented
Jan 20, 2026

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Contributor
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the polyfill's custom timeline.
@sebmarkbage
Cancel animation when a custom Timeline is used
817bd79
The clean up function of the custom timeline doesn't necessarily clean up
the animation. Just the timeline's internal state.
@sebmarkbage
sebmarkbage
merged commit d290875
into
react:mainJan 20, 2026

14 of 15 checks passed

@github-actionsgithub-actionsBot
added
the 
React Core Team
Opened by a member of the React Core Team
label
Jan 20, 2026
@react-sizebot
react-sizebot
commented
Jan 20, 2026

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Comparing: d343c39...817bd79
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=608.73 kB608.73 kB=107.65 kB107.65 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=674.61 kB674.66 kB=118.59 kB118.59 kB
facebook-www/ReactDOM-prod.classic.js=694.11 kB694.11 kB=122.02 kB122.02 kB
facebook-www/ReactDOM-prod.modern.js=684.50 kB684.50 kB=120.42 kB120.42 kB
Significant size changes
Includes any change greater than 0.2%:
(No significant changes)

Generated by 🚫 dangerJS against 817bd79
github-actionsBot
pushed a commit
that referenced
this pull request
Jan 20, 2026
@sebmarkbage
Cancel animation when a custom Timeline is used (#35567)
6722cbc
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean
up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the
polyfill's custom timeline.
DiffTrain build for [d290875](d290875)
@nextjs-botnextjs-bot
mentioned this pull request
Jan 20, 2026
 Merged

sebmarkbage pushed a commit
to vercel/next.js
that referenced
this pull request
Jan 20, 2026
@nextjs-bot
Upgrade React from41b3e9a6-20260119tod2908752-20260119(#88774)
9e33529
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
@rubennorterubennorte
mentioned this pull request
Jun 5, 2026
 Closed

m-kawafuji pushed a commit
to m-kawafuji/next.js
that referenced
this pull request
Aug 8, 2026
@nextjs-bot@m-kawafuji
Upgrade React from41b3e9a6-20260119tod2908752-20260119(vercel…
b19ed31
…#88774)
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
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@acdliteacdliteAwaiting requested review from acdlite

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2 participants

@sebmarkbage@react-sizebot

, '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('^' + ".*" + '
Cancel animation when a custom Timeline is used by sebmarkbage · Pull Request #35567 · react/react · GitHub
Skip to content
Cancel animation when a custom Timeline is used - #35567
Merged
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Jan 20, 2026
Merged
Cancel animation when a custom Timeline is used#35567
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Conversation
@sebmarkbage
@sebmarkbagesebmarkbage
commented
Jan 20, 2026

Copy link


Copy Markdown

Contributor
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the polyfill's custom timeline.
@sebmarkbage
Cancel animation when a custom Timeline is used
817bd79
The clean up function of the custom timeline doesn't necessarily clean up
the animation. Just the timeline's internal state.
@sebmarkbage
sebmarkbage
merged commit d290875
into
react:mainJan 20, 2026

14 of 15 checks passed

@github-actionsgithub-actionsBot
added
the 
React Core Team
Opened by a member of the React Core Team
label
Jan 20, 2026
@react-sizebot
react-sizebot
commented
Jan 20, 2026

Copy link


Copy Markdown

Comparing: d343c39...817bd79
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=608.73 kB608.73 kB=107.65 kB107.65 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=674.61 kB674.66 kB=118.59 kB118.59 kB
facebook-www/ReactDOM-prod.classic.js=694.11 kB694.11 kB=122.02 kB122.02 kB
facebook-www/ReactDOM-prod.modern.js=684.50 kB684.50 kB=120.42 kB120.42 kB
Significant size changes
Includes any change greater than 0.2%:
(No significant changes)

Generated by 🚫 dangerJS against 817bd79
github-actionsBot
pushed a commit
that referenced
this pull request
Jan 20, 2026
@sebmarkbage
Cancel animation when a custom Timeline is used (#35567)
6722cbc
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean
up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the
polyfill's custom timeline.
DiffTrain build for [d290875](d290875)
@nextjs-botnextjs-bot
mentioned this pull request
Jan 20, 2026
 Merged

sebmarkbage pushed a commit
to vercel/next.js
that referenced
this pull request
Jan 20, 2026
@nextjs-bot
Upgrade React from41b3e9a6-20260119tod2908752-20260119(#88774)
9e33529
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
@rubennorterubennorte
mentioned this pull request
Jun 5, 2026
 Closed

m-kawafuji pushed a commit
to m-kawafuji/next.js
that referenced
this pull request
Aug 8, 2026
@nextjs-bot@m-kawafuji
Upgrade React from41b3e9a6-20260119tod2908752-20260119(vercel…
b19ed31
…#88774)
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
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@acdliteacdliteAwaiting requested review from acdlite

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2 participants

@sebmarkbage@react-sizebot

, '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('^' + ".*" + '
Cancel animation when a custom Timeline is used by sebmarkbage · Pull Request #35567 · react/react · GitHub
Skip to content
Cancel animation when a custom Timeline is used - #35567
Merged
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Jan 20, 2026
Merged
Cancel animation when a custom Timeline is used#35567
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Conversation
@sebmarkbage
@sebmarkbagesebmarkbage
commented
Jan 20, 2026

Copy link


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Contributor
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the polyfill's custom timeline.
@sebmarkbage
Cancel animation when a custom Timeline is used
817bd79
The clean up function of the custom timeline doesn't necessarily clean up
the animation. Just the timeline's internal state.
@sebmarkbage
sebmarkbage
merged commit d290875
into
react:mainJan 20, 2026

14 of 15 checks passed

@github-actionsgithub-actionsBot
added
the 
React Core Team
Opened by a member of the React Core Team
label
Jan 20, 2026
@react-sizebot
react-sizebot
commented
Jan 20, 2026

Copy link


Copy Markdown

Comparing: d343c39...817bd79
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=608.73 kB608.73 kB=107.65 kB107.65 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=674.61 kB674.66 kB=118.59 kB118.59 kB
facebook-www/ReactDOM-prod.classic.js=694.11 kB694.11 kB=122.02 kB122.02 kB
facebook-www/ReactDOM-prod.modern.js=684.50 kB684.50 kB=120.42 kB120.42 kB
Significant size changes
Includes any change greater than 0.2%:
(No significant changes)

Generated by 🚫 dangerJS against 817bd79
github-actionsBot
pushed a commit
that referenced
this pull request
Jan 20, 2026
@sebmarkbage
Cancel animation when a custom Timeline is used (#35567)
6722cbc
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean
up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the
polyfill's custom timeline.
DiffTrain build for [d290875](d290875)
@nextjs-botnextjs-bot
mentioned this pull request
Jan 20, 2026
 Merged

sebmarkbage pushed a commit
to vercel/next.js
that referenced
this pull request
Jan 20, 2026
@nextjs-bot
Upgrade React from41b3e9a6-20260119tod2908752-20260119(#88774)
9e33529
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
@rubennorterubennorte
mentioned this pull request
Jun 5, 2026
 Closed

m-kawafuji pushed a commit
to m-kawafuji/next.js
that referenced
this pull request
Aug 8, 2026
@nextjs-bot@m-kawafuji
Upgrade React from41b3e9a6-20260119tod2908752-20260119(vercel…
b19ed31
…#88774)
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
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2 participants

@sebmarkbage@react-sizebot

, '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" + '
Cancel animation when a custom Timeline is used by sebmarkbage · Pull Request #35567 · react/react · GitHub
Skip to content
Cancel animation when a custom Timeline is used - #35567
Merged
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Jan 20, 2026
Merged
Cancel animation when a custom Timeline is used#35567
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Conversation
@sebmarkbage
@sebmarkbagesebmarkbage
commented
Jan 20, 2026

Copy link


Copy Markdown

Contributor
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the polyfill's custom timeline.
@sebmarkbage
Cancel animation when a custom Timeline is used
817bd79
The clean up function of the custom timeline doesn't necessarily clean up
the animation. Just the timeline's internal state.
@sebmarkbage
sebmarkbage
merged commit d290875
into
react:mainJan 20, 2026

14 of 15 checks passed

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Comparing: d343c39...817bd79
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=608.73 kB608.73 kB=107.65 kB107.65 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=674.61 kB674.66 kB=118.59 kB118.59 kB
facebook-www/ReactDOM-prod.classic.js=694.11 kB694.11 kB=122.02 kB122.02 kB
facebook-www/ReactDOM-prod.modern.js=684.50 kB684.50 kB=120.42 kB120.42 kB
Significant size changes
Includes any change greater than 0.2%:
(No significant changes)

Generated by 🚫 dangerJS against 817bd79
github-actionsBot
pushed a commit
that referenced
this pull request
Jan 20, 2026
@sebmarkbage
Cancel animation when a custom Timeline is used (#35567)
6722cbc
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean
up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the
polyfill's custom timeline.
DiffTrain build for [d290875](d290875)
@nextjs-botnextjs-bot
mentioned this pull request
Jan 20, 2026
 Merged

sebmarkbage pushed a commit
to vercel/next.js
that referenced
this pull request
Jan 20, 2026
@nextjs-bot
Upgrade React from41b3e9a6-20260119tod2908752-20260119(#88774)
9e33529
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
@rubennorterubennorte
mentioned this pull request
Jun 5, 2026
 Closed

m-kawafuji pushed a commit
to m-kawafuji/next.js
that referenced
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Aug 8, 2026
@nextjs-bot@m-kawafuji
Upgrade React from41b3e9a6-20260119tod2908752-20260119(vercel…
b19ed31
…#88774)
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
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, '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('^' + ".*" + '
Cancel animation when a custom Timeline is used by sebmarkbage · Pull Request #35567 · react/react · GitHub
Skip to content
Cancel animation when a custom Timeline is used - #35567
Merged
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Jan 20, 2026
Merged
Cancel animation when a custom Timeline is used#35567
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Conversation
@sebmarkbage
@sebmarkbagesebmarkbage
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Jan 20, 2026

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Contributor
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the polyfill's custom timeline.
@sebmarkbage
Cancel animation when a custom Timeline is used
817bd79
The clean up function of the custom timeline doesn't necessarily clean up
the animation. Just the timeline's internal state.
@sebmarkbage
sebmarkbage
merged commit d290875
into
react:mainJan 20, 2026

14 of 15 checks passed

@github-actionsgithub-actionsBot
added
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Opened by a member of the React Core Team
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Jan 20, 2026
@react-sizebot
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Comparing: d343c39...817bd79
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=608.73 kB608.73 kB=107.65 kB107.65 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=674.61 kB674.66 kB=118.59 kB118.59 kB
facebook-www/ReactDOM-prod.classic.js=694.11 kB694.11 kB=122.02 kB122.02 kB
facebook-www/ReactDOM-prod.modern.js=684.50 kB684.50 kB=120.42 kB120.42 kB
Significant size changes
Includes any change greater than 0.2%:
(No significant changes)

Generated by 🚫 dangerJS against 817bd79
github-actionsBot
pushed a commit
that referenced
this pull request
Jan 20, 2026
@sebmarkbage
Cancel animation when a custom Timeline is used (#35567)
6722cbc
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean
up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the
polyfill's custom timeline.
DiffTrain build for [d290875](d290875)
@nextjs-botnextjs-bot
mentioned this pull request
Jan 20, 2026
 Merged

sebmarkbage pushed a commit
to vercel/next.js
that referenced
this pull request
Jan 20, 2026
@nextjs-bot
Upgrade React from41b3e9a6-20260119tod2908752-20260119(#88774)
9e33529
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
@rubennorterubennorte
mentioned this pull request
Jun 5, 2026
 Closed

m-kawafuji pushed a commit
to m-kawafuji/next.js
that referenced
this pull request
Aug 8, 2026
@nextjs-bot@m-kawafuji
Upgrade React from41b3e9a6-20260119tod2908752-20260119(vercel…
b19ed31
…#88774)
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
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@acdliteacdliteAwaiting requested review from acdlite

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@sebmarkbage@react-sizebot

, '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('^' + ".*" + '
Cancel animation when a custom Timeline is used by sebmarkbage · Pull Request #35567 · react/react · GitHub
Skip to content
Cancel animation when a custom Timeline is used - #35567
Merged
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Jan 20, 2026
Merged
Cancel animation when a custom Timeline is used#35567
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Conversation
@sebmarkbage
@sebmarkbagesebmarkbage
commented
Jan 20, 2026

Copy link


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Contributor
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the polyfill's custom timeline.
@sebmarkbage
Cancel animation when a custom Timeline is used
817bd79
The clean up function of the custom timeline doesn't necessarily clean up
the animation. Just the timeline's internal state.
@sebmarkbage
sebmarkbage
merged commit d290875
into
react:mainJan 20, 2026

14 of 15 checks passed

@github-actionsgithub-actionsBot
added
the 
React Core Team
Opened by a member of the React Core Team
label
Jan 20, 2026
@react-sizebot
react-sizebot
commented
Jan 20, 2026

Copy link


Copy Markdown

Comparing: d343c39...817bd79
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=608.73 kB608.73 kB=107.65 kB107.65 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=674.61 kB674.66 kB=118.59 kB118.59 kB
facebook-www/ReactDOM-prod.classic.js=694.11 kB694.11 kB=122.02 kB122.02 kB
facebook-www/ReactDOM-prod.modern.js=684.50 kB684.50 kB=120.42 kB120.42 kB
Significant size changes
Includes any change greater than 0.2%:
(No significant changes)

Generated by 🚫 dangerJS against 817bd79
github-actionsBot
pushed a commit
that referenced
this pull request
Jan 20, 2026
@sebmarkbage
Cancel animation when a custom Timeline is used (#35567)
6722cbc
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean
up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the
polyfill's custom timeline.
DiffTrain build for [d290875](d290875)
@nextjs-botnextjs-bot
mentioned this pull request
Jan 20, 2026
 Merged

sebmarkbage pushed a commit
to vercel/next.js
that referenced
this pull request
Jan 20, 2026
@nextjs-bot
Upgrade React from41b3e9a6-20260119tod2908752-20260119(#88774)
9e33529
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
@rubennorterubennorte
mentioned this pull request
Jun 5, 2026
 Closed

m-kawafuji pushed a commit
to m-kawafuji/next.js
that referenced
this pull request
Aug 8, 2026
@nextjs-bot@m-kawafuji
Upgrade React from41b3e9a6-20260119tod2908752-20260119(vercel…
b19ed31
…#88774)
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
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2 participants

@sebmarkbage@react-sizebot

, '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); }
})();
})();
Cancel animation when a custom Timeline is used by sebmarkbage · Pull Request #35567 · react/react · GitHub
Skip to content
Cancel animation when a custom Timeline is used - #35567
Merged
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Jan 20, 2026
Merged
Cancel animation when a custom Timeline is used#35567
sebmarkbage merged 1 commit into
react:mainfrom 
sebmarkbage:gesturefirefoxbug
Conversation
@sebmarkbage
@sebmarkbagesebmarkbage
commented
Jan 20, 2026

Copy link


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Contributor
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the polyfill's custom timeline.
@sebmarkbage
Cancel animation when a custom Timeline is used
817bd79
The clean up function of the custom timeline doesn't necessarily clean up
the animation. Just the timeline's internal state.
@sebmarkbage
sebmarkbage
merged commit d290875
into
react:mainJan 20, 2026

14 of 15 checks passed

@github-actionsgithub-actionsBot
added
the 
React Core Team
Opened by a member of the React Core Team
label
Jan 20, 2026
@react-sizebot
react-sizebot
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Jan 20, 2026

Copy link


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Comparing: d343c39...817bd79
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=608.73 kB608.73 kB=107.65 kB107.65 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=674.61 kB674.66 kB=118.59 kB118.59 kB
facebook-www/ReactDOM-prod.classic.js=694.11 kB694.11 kB=122.02 kB122.02 kB
facebook-www/ReactDOM-prod.modern.js=684.50 kB684.50 kB=120.42 kB120.42 kB
Significant size changes
Includes any change greater than 0.2%:
(No significant changes)

Generated by 🚫 dangerJS against 817bd79
github-actionsBot
pushed a commit
that referenced
this pull request
Jan 20, 2026
@sebmarkbage
Cancel animation when a custom Timeline is used (#35567)
6722cbc
Follow up to #35559.
The clean up function of the custom timeline doesn't necessarily clean
up the animation. Just the timeline's internal state.
This affects Firefox which doesn't support ScrollTimeline so uses the
polyfill's custom timeline.
DiffTrain build for [d290875](d290875)
@nextjs-botnextjs-bot
mentioned this pull request
Jan 20, 2026
 Merged

sebmarkbage pushed a commit
to vercel/next.js
that referenced
this pull request
Jan 20, 2026
@nextjs-bot
Upgrade React from41b3e9a6-20260119tod2908752-20260119(#88774)
9e33529
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
@rubennorterubennorte
mentioned this pull request
Jun 5, 2026
 Closed

m-kawafuji pushed a commit
to m-kawafuji/next.js
that referenced
this pull request
Aug 8, 2026
@nextjs-bot@m-kawafuji
Upgrade React from41b3e9a6-20260119tod2908752-20260119(vercel…
b19ed31
…#88774)
[diff
react/react@41b3e9a6...d2908752](react/react@41b3e9a...d290875)
<details>
<summary>React upstream changes</summary>
- react/react#35567
- react/react#35566
- react/react#35565
- react/react#35564
- react/react#35559
- react/react#35556
</details>
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@acdliteacdliteAwaiting requested review from acdlite

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2 participants

@sebmarkbage@react-sizebot