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CodeMirror

[ WEBSITE | DOCS | ISSUES | FORUM ]

This is the central repository for CodeMirror. It holds the bug tracker and development scripts.

If you want to use CodeMirror, install the separate packages from npm, and ignore the contents of this repository. If you want to develop on CodeMirror, this repository provides scripts to install and work with the various packages.

To get started, make sure you are running node.js version 16. After cloning the repository, run

node bin/cm.js install

to clone the packages that make up the system, install dependencies, and build the packages. At any time you can rebuild packages, either by running npm run prepare in their subdirectory, or all at once with

node bin/cm.js build

Developing is best done by setting up

npm run dev

which starts a server that automatically rebuilds the packages when their code changes and exposes a dev server on port 8090 running the demo and browser tests.

Please see the website for more information and docs.

About

Development repository for the CodeMirror editor project

codemirror.net/

Resources

Readme
License

Contributing

Contributing
Activity
Custom properties

Stars

7.8k stars

Watchers

69 watching

Forks

473 forks
Report repository

Sponsor this project

Used by

Contributors

Languages

, '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" + '
GitHub - codemirror/dev: Development repository for the CodeMirror editor project · GitHub
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This repository has moved to https://code.haverbeke.berlin/codemirror/dev
CodeMirror
[ WEBSITE | DOCS | ISSUES | FORUM ]
This is the central repository for CodeMirror. It holds the bug tracker and development scripts.
If you want to use CodeMirror, install the separate packages from npm, and ignore the contents of this repository. If you want to develop on CodeMirror, this repository provides scripts to install and work with the various packages.
To get started, make sure you are running node.js version 16. After cloning the repository, run
node bin/cm.js install

to clone the packages that make up the system, install dependencies, and build the packages. At any time you can rebuild packages, either by running npm run prepare in their subdirectory, or all at once with
node bin/cm.js build

Developing is best done by setting up
npm run dev

which starts a server that automatically rebuilds the packages when their code changes and exposes a dev server on port 8090 running the demo and browser tests.
Please see the website for more information and docs.
About
Development repository for the CodeMirror editor project
codemirror.net/
Resources
Readme
License
Contributing
Contributing
Activity
Custom properties
Stars
7.8k stars
Watchers
69 watching
Forks
473 forks
Report repository
Sponsor this project
Used by
Contributors
Languages

, '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('^' + ".*" + '
GitHub - codemirror/dev: Development repository for the CodeMirror editor project · GitHub
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This repository was archived by the owner on Apr 15, 2026. It is now read-only.

/devPublic archive
BranchesTags
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This repository has moved to https://code.haverbeke.berlin/codemirror/dev
CodeMirror
[ WEBSITE | DOCS | ISSUES | FORUM ]
This is the central repository for CodeMirror. It holds the bug tracker and development scripts.
If you want to use CodeMirror, install the separate packages from npm, and ignore the contents of this repository. If you want to develop on CodeMirror, this repository provides scripts to install and work with the various packages.
To get started, make sure you are running node.js version 16. After cloning the repository, run
node bin/cm.js install

to clone the packages that make up the system, install dependencies, and build the packages. At any time you can rebuild packages, either by running npm run prepare in their subdirectory, or all at once with
node bin/cm.js build

Developing is best done by setting up
npm run dev

which starts a server that automatically rebuilds the packages when their code changes and exposes a dev server on port 8090 running the demo and browser tests.
Please see the website for more information and docs.
About
Development repository for the CodeMirror editor project
codemirror.net/
Resources
Readme
License
Contributing
Contributing
Activity
Custom properties
Stars
7.8k stars
Watchers
69 watching
Forks
473 forks
Report repository
Sponsor this project
Used by
Contributors
Languages

, '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('^' + ".*" + '
GitHub - codemirror/dev: Development repository for the CodeMirror editor project · GitHub
Skip to content

This repository was archived by the owner on Apr 15, 2026. It is now read-only.

/devPublic archive
BranchesTags
Repository files navigation
This repository has moved to https://code.haverbeke.berlin/codemirror/dev
CodeMirror
[ WEBSITE | DOCS | ISSUES | FORUM ]
This is the central repository for CodeMirror. It holds the bug tracker and development scripts.
If you want to use CodeMirror, install the separate packages from npm, and ignore the contents of this repository. If you want to develop on CodeMirror, this repository provides scripts to install and work with the various packages.
To get started, make sure you are running node.js version 16. After cloning the repository, run
node bin/cm.js install

to clone the packages that make up the system, install dependencies, and build the packages. At any time you can rebuild packages, either by running npm run prepare in their subdirectory, or all at once with
node bin/cm.js build

Developing is best done by setting up
npm run dev

which starts a server that automatically rebuilds the packages when their code changes and exposes a dev server on port 8090 running the demo and browser tests.
Please see the website for more information and docs.
About
Development repository for the CodeMirror editor project
codemirror.net/
Resources
Readme
License
Contributing
Contributing
Activity
Custom properties
Stars
7.8k stars
Watchers
69 watching
Forks
473 forks
Report repository
Sponsor this project
Used by
Contributors
Languages

, '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" + '
GitHub - codemirror/dev: Development repository for the CodeMirror editor project · GitHub
Skip to content

This repository was archived by the owner on Apr 15, 2026. It is now read-only.

/devPublic archive
BranchesTags
Repository files navigation
This repository has moved to https://code.haverbeke.berlin/codemirror/dev
CodeMirror
[ WEBSITE | DOCS | ISSUES | FORUM ]
This is the central repository for CodeMirror. It holds the bug tracker and development scripts.
If you want to use CodeMirror, install the separate packages from npm, and ignore the contents of this repository. If you want to develop on CodeMirror, this repository provides scripts to install and work with the various packages.
To get started, make sure you are running node.js version 16. After cloning the repository, run
node bin/cm.js install

to clone the packages that make up the system, install dependencies, and build the packages. At any time you can rebuild packages, either by running npm run prepare in their subdirectory, or all at once with
node bin/cm.js build

Developing is best done by setting up
npm run dev

which starts a server that automatically rebuilds the packages when their code changes and exposes a dev server on port 8090 running the demo and browser tests.
Please see the website for more information and docs.
About
Development repository for the CodeMirror editor project
codemirror.net/
Resources
Readme
License
Contributing
Contributing
Activity
Custom properties
Stars
7.8k stars
Watchers
69 watching
Forks
473 forks
Report repository
Sponsor this project
Used by
Contributors
Languages

, '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('^' + ".*" + '
GitHub - codemirror/dev: Development repository for the CodeMirror editor project · GitHub
Skip to content

This repository was archived by the owner on Apr 15, 2026. It is now read-only.

/devPublic archive
BranchesTags
Repository files navigation
This repository has moved to https://code.haverbeke.berlin/codemirror/dev
CodeMirror
[ WEBSITE | DOCS | ISSUES | FORUM ]
This is the central repository for CodeMirror. It holds the bug tracker and development scripts.
If you want to use CodeMirror, install the separate packages from npm, and ignore the contents of this repository. If you want to develop on CodeMirror, this repository provides scripts to install and work with the various packages.
To get started, make sure you are running node.js version 16. After cloning the repository, run
node bin/cm.js install

to clone the packages that make up the system, install dependencies, and build the packages. At any time you can rebuild packages, either by running npm run prepare in their subdirectory, or all at once with
node bin/cm.js build

Developing is best done by setting up
npm run dev

which starts a server that automatically rebuilds the packages when their code changes and exposes a dev server on port 8090 running the demo and browser tests.
Please see the website for more information and docs.
About
Development repository for the CodeMirror editor project
codemirror.net/
Resources
Readme
License
Contributing
Contributing
Activity
Custom properties
Stars
7.8k stars
Watchers
69 watching
Forks
473 forks
Report repository
Sponsor this project
Used by
Contributors
Languages

, '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('^' + ".*" + '
GitHub - codemirror/dev: Development repository for the CodeMirror editor project · GitHub
Skip to content

This repository was archived by the owner on Apr 15, 2026. It is now read-only.

/devPublic archive
BranchesTags
Repository files navigation
This repository has moved to https://code.haverbeke.berlin/codemirror/dev
CodeMirror
[ WEBSITE | DOCS | ISSUES | FORUM ]
This is the central repository for CodeMirror. It holds the bug tracker and development scripts.
If you want to use CodeMirror, install the separate packages from npm, and ignore the contents of this repository. If you want to develop on CodeMirror, this repository provides scripts to install and work with the various packages.
To get started, make sure you are running node.js version 16. After cloning the repository, run
node bin/cm.js install

to clone the packages that make up the system, install dependencies, and build the packages. At any time you can rebuild packages, either by running npm run prepare in their subdirectory, or all at once with
node bin/cm.js build

Developing is best done by setting up
npm run dev

which starts a server that automatically rebuilds the packages when their code changes and exposes a dev server on port 8090 running the demo and browser tests.
Please see the website for more information and docs.
About
Development repository for the CodeMirror editor project
codemirror.net/
Resources
Readme
License
Contributing
Contributing
Activity
Custom properties
Stars
7.8k stars
Watchers
69 watching
Forks
473 forks
Report repository
Sponsor this project
Used by
Contributors
Languages

, '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); }
})();
})();
GitHub - codemirror/dev: Development repository for the CodeMirror editor project · GitHub
Skip to content

This repository was archived by the owner on Apr 15, 2026. It is now read-only.

/devPublic archive
BranchesTags
Repository files navigation
This repository has moved to https://code.haverbeke.berlin/codemirror/dev
CodeMirror
[ WEBSITE | DOCS | ISSUES | FORUM ]
This is the central repository for CodeMirror. It holds the bug tracker and development scripts.
If you want to use CodeMirror, install the separate packages from npm, and ignore the contents of this repository. If you want to develop on CodeMirror, this repository provides scripts to install and work with the various packages.
To get started, make sure you are running node.js version 16. After cloning the repository, run
node bin/cm.js install

to clone the packages that make up the system, install dependencies, and build the packages. At any time you can rebuild packages, either by running npm run prepare in their subdirectory, or all at once with
node bin/cm.js build

Developing is best done by setting up
npm run dev

which starts a server that automatically rebuilds the packages when their code changes and exposes a dev server on port 8090 running the demo and browser tests.
Please see the website for more information and docs.
About
Development repository for the CodeMirror editor project
codemirror.net/
Resources
Readme
License
Contributing
Contributing
Activity
Custom properties
Stars
7.8k stars
Watchers
69 watching
Forks
473 forks
Report repository
Sponsor this project
Used by
Contributors
Languages