stylex
Copilot instructions10k starsChanged 3 years agoMITView on GitHub
Focus on critical issues only. Do not nitpick naming, style preferences, or suggest refactors on bug-fix PRs.
We split this copilot-instructions.md into the rules it gives an agent
2 rules. About 0 are common, 1 is distinctive, and 1 is very specific to this project.
≈0
Common · estimate
Many files like this have a rule of this kind.
≈1
Distinctive · estimate
This author's own choices. Worth a look.
1
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Very specific: line 10
Flow syntax: Use modern Flow — Readonly<> not $ReadOnly<>, unknown not mixed, ReadonlyArray not $ReadOnlyArray.
- Distinctive: line 21
Must include a changelog entry.
≈ “Common” is an estimate: at least 1 in 5 of the 3,669 Copilot instructions files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
StyleX Code Review Guidelines
Focus on critical issues only. Do not nitpick naming, style preferences, or suggest refactors on bug-fix PRs.
Must-haves
- CLA: External contributors must sign the CLA at https://code.facebook.com/cla. Flag if the
CLA Signedlabel is missing on external PRs. - CI signals: Flag if any CI check is failing and the PR does not acknowledge it.
- Tests: New babel-plugin features or bug fixes must include tests. Prefer
toMatchInlineSnapshot()for all assertion snapshots. - Flow syntax: Use modern Flow —
Readonly<>not$ReadOnly<>,unknownnotmixed,ReadonlyArraynot$ReadOnlyArray. - Lint and formatting: Code must pass eslint and prettier. Flag obvious violations.
Babel plugin
- New compile-time APIs must throw at runtime with a clear error message.
- New APIs should include documentation, eslint plugin support, and tests.
- Review test snapshot output and compiled JS/CSS to verify no regressions in generated code.
Release PRs
- Must include a changelog entry.
- Version bumps must be consistent across all workspace packages.
- Release blog posts should credit community contributors with
(Thanks [username](url)!)format.
Documentation
- Code examples in docs and blog posts must use valid CSS and JS syntax.
Trending
Quiet since September.about the whole repository
Who's talking about facebook/stylex
- meta/stylex“[roadmap] StyleX v1.0.0”GitHub · Dec 3, 2025 · 33 reactions
- A Hacker News story“Facebook Open Sources StyleX”Hacker News · Dec 5, 2023 · 27 points
- evanw/esbuild“Feature Request: Add polyfill for CSS `light-dark()`”GitHub · Jun 1, 2024 · 20 reactions
- @samuel.fm“Meta has open sourced StyleX 🥳 https://github.com/facebook/stylex”Bluesky · Dec 5, 2023 · 9 likes
- meta/stylex“0.13.0 task list”GitHub · May 1, 2025 · 7 reactions
The biggest 5 of 58 mentions linking to the repository that our crawl found. Each line is their own headline.
See all 58
Talked about on GitHub, Bluesky, Stack Overflow and Hacker News (58 times).
On GitHub · 50
- Dec 3, 2025[roadmap] StyleX v1.0.0 — meta/stylex33 reactions
- Jun 1, 2024Feature Request: Add polyfill for CSS `light-dark()` — evanw/esbuild20 reactions
- May 1, 20250.13.0 task list — meta/stylex7 reactions · 3 comments
- Dec 16, 2025[FEATURE] Simple sx={} syntax as an alternative to stylex.props — Dwlad90/stylex-swc-plugin6 reactions · 7 comments
- May 6, 2026`defineConsts` breakpoints don't support `enableMediaQueryOrder`, causing non-deterministic CSS ordering — meta/stylex5 reactions · 4 comments
45 more on GitHub
- Apr 1, 2026[feat] Experimental nested APIs — meta/stylex5 reactions · 6 comments
- Dec 22, 2025[fix] Better media query sorting — meta/stylex5 reactions
- Aug 28, 2025can we get a more ergonomic api for devx coming from styled components / emotion — meta/stylex5 reactions · 7 comments
- Mar 20, 2026fix(unplugin): prevent file handle leaks in Vitest (#1533) — meta/stylex4 reactions · 5 comments
- Nov 8, 2025[playground] Introduce new potential replacement playground — meta/stylex4 reactions · 6 comments
- Oct 27, 2025[babel-plugin] Support nested objects in `defineConsts` — meta/stylex4 reactions · 7 comments
- Aug 21, 20250.16 TODO — meta/stylex4 reactions
- Jun 14, 2025Support names export statment — meta/stylex4 reactions · 1 comment
- Jan 2, 2025[babel-plugin] Allow `stylex.create` nested within TS namespaces (and more?) — meta/stylex4 reactions · 2 comments
- Jun 8, 2024(Reactive Variables) Support of swapping underlying variables while using hierarchical variable references — meta/stylex4 reactions · 15 comments
- Apr 29, 2024Feat/cli — meta/stylex4 reactions · 3 comments
- Apr 3, 2024Detect intended Media query boundaries by order. — meta/stylex4 reactions · 7 comments
- Dec 16, 2023add support for stylex — angular/angular4 reactions · 3 comments
- Feb 16, 2026[babel-plugin] fix invalid @ rule body when using dynamic styles in pseudo elements — meta/stylex3 reactions · 1 comment
- May 20, 2025TypeScript error while using `stylex.create` after 0.13.0 update - the inferred type cannot be named without a reference — meta/stylex3 reactions · 13 comments
- May 13, 2026Missing library in Supported Ecosystem - StyleX — thereactfoundation/react.foundation2 reactions · 10 comments
- Mar 17, 2026(babel-plugin): Add layersBefore/layersAfter config to processStylexR… — meta/stylex2 reactions · 2 comments
- Jan 6, 2026NPX Create Stylex App — meta/stylex2 reactions · 5 comments
- Nov 4, 2025Add example on chaining keyframes — meta/stylex2 reactions · 3 comments
- Oct 4, 2025[eslint-plugin] enhance validation for ternary and logical expressions in style properties — meta/stylex2 reactions · 5 comments
- Sep 20, 2025[example] add storybook example with stylex — meta/stylex2 reactions · 5 comments
- May 28, 2025[eslint-plugin] support validImports options for all rules — meta/stylex2 reactions
- Apr 12, 2025allow passing @stylexjs/babel-plugin aliases through react-strict-dom/babel-preset — react/react-strict-dom2 reactions · 4 comments
- Apr 11, 2025Replace $Diff in StyleXTypes — meta/stylex2 reactions · 1 comment
- Feb 22, 2025feat: create media query transformer to ensure last query wins — meta/stylex2 reactions · 4 comments
- Nov 24, 2024feat: add postcss-plugin — meta/stylex2 reactions · 1 comment
- Jul 2, 2024Stop transforming textAlign:start/end — meta/stylex2 reactions · 3 comments
- May 11, 2024feat(@stylexjs/eslint-plugin): Accept { from: string, as: string } syntax in validImports option for RSD — meta/stylex2 reactions · 2 comments
- Apr 25, 2024TypeError: String.prototype.concat called on null or undefined (v0.6.1) — meta/stylex2 reactions · 13 comments
- Apr 23, 2024Nested pseudo classes within pseudo elements — meta/stylex2 reactions · 5 comments
- Jan 9, 2024Safe typings for TypeScript v4 — meta/stylex2 reactions · 12 comments
- Dec 21, 2023CSS parser failed to execute insertRule while using multiple rules string from defineVars — meta/stylex2 reactions · 3 comments
- Dec 13, 2023Perf: Remove runtime injection from runtime — meta/stylex2 reactions · 7 comments
- Dec 6, 2023No TypeScript autocomplete for CSS properties when authoring styles in Next.js application — meta/stylex2 reactions · 7 comments
- Sep 24, 2026Bump the minor-and-patch group across 1 directory with 16 updates — robertweisbecker/base-xyz1 reaction · 1 comment
- Mar 14, 2026[eslint-plugin] accept bare numbers for time-related properties — meta/stylex1 reaction · 2 comments
- Mar 13, 2026chore(examples/37_css-stylex): use `@stylexjs/unplugin` — wakujs/waku1 reaction · 4 comments
- Mar 6, 2026feat: allow overriding type of `stylex.env` in TypeScript — meta/stylex1 reaction · 2 comments
- Dec 18, 2025[babel-plugin] fix named export detection — meta/stylex1 reaction · 2 comments
- Nov 30, 2025[babel-plugin] introduce browser bundle — meta/stylex1 reaction
- Nov 11, 2025Fix internal meta sync — meta/stylex1 reaction · 2 comments
- Oct 27, 2025[eslint-plugin] Add transform-media-query rule and soft validation config — meta/stylex1 reaction · 3 comments
- Oct 15, 2025fix playground link — meta/stylex1 reaction · 1 comment
- Sep 26, 2025[eslint-plugin] eslint plugin doesn't specify eslint version compat — meta/stylex1 reaction
- Sep 26, 2025[eslint] Split nonstandard rules into stylex-no-nonstandard-styles.js — meta/stylex1 reaction · 4 comments
On Bluesky · 5
- Dec 5, 2023Meta has open sourced StyleX 🥳 https://github.com/facebook/stylex — @samuel.fm9 likes and reposts · 3 replies
- Dec 15, 2023🎉 Celebrating! 🎉 (500+ new stars) 📦 facebook / stylex ⭐ 5,441 (+556) 🗒 JavaScript StyleX is the styling system for ambitious user… — @github-trending-js.bsky.social7 likes and reposts · 1 reply
- Dec 7, 2023🎉 Celebrating! 🎉 (500+ new stars) 📦 facebook / stylex ⭐ 3,056 (+953) 🗒 JavaScript StyleX is the styling system for ambitious user… — @github-trending-js.bsky.social2 likes and reposts · 1 reply
- Jan 11, 2026📦 facebook / stylex ⭐ 9,056 (+34) 🗒 JavaScript StyleX is the styling system for ambitious user interfaces. — @github-trending-js.bsky.social1 likes and repost
- Dec 8, 2023🎉 Celebrating! 🎉 (500+ new stars) 📦 facebook / stylex ⭐ 3,056 (+953) 🗒 JavaScript StyleX is the styling system for ambitious user… — @github-trending.bsky.social0 likes and reposts · 1 reply
On Stack Overflow · 2
- Mar 24, 2024StyleX defineVars Not Applying in Next.js(turboRepo) Project1 vote
- Mar 24, 2024How to install StyleX in a new React project0 votes
On Hacker News · 1
- Dec 5, 2023Facebook Open Sources StyleX27 points · 3 comments
Where files are headingNew Copilot instructions files have more rules about branches and pull requests, and fewer about code style.
Of the Copilot instructions files we read, the 2,297 first seen in the last six months, against the older ones: the kind of rule that gained most share, and the kind that lost most. About files like this in general, not this one, and an estimate, since a kind is a pattern in the words.
Does it work?
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Your trail
Files you open will collect here, so you can find them again.
Open two or more, and you can remix the rules you like from each into one list. Kept in this browser only.
Now do this for your own.
Bring your CLAUDE.md, AGENTS.md or skills. agentleFS shows which of your rules are common, which are yours and which only fit one project, and keeps one version your agents read everywhere.

