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Mathias Picker 27e74c4df7 docs: add auto-generated browser support page (#18276 ) ## Summary Adds a [Browser support](https://github.com/MathiasWP/svelte/blob/document-pipeline-draft/documentation/docs/07-misc/05-browser-support.md) page listing the minimum browser versions Svelte's runtime and compiler output require. The page (headline floor + per-feature requirements) is auto-generated by `packages/svelte/scripts/generate-browser-support.js`, which scans the code Svelte actually ships against the [web-features](https://github.com/web-platform-dx/web-features) Baseline dataset and resolves results to concrete browser versions via [baseline-browser-mapping](https://github.com/web-platform-dx/baseline-browser-mapping). CI fails if a PR moves the floor without regenerating the page. For 5.55.9 the floor is Baseline 2020: Chrome/Edge 87, Firefox 83, Safari 14. ## How it works 1. Headline floor. Each runtime entry from `pkg.exports` is bundled with rollup using production conditions, then walked with TypeScript's compiler API + TypeChecker. The walker (`browser-support.detector.js`) flags any web-features ID the runtime references; the highest Baseline year among them is the floor. 2. Per-feature requirements. Every user-facing surface is enumerated programmatically — every `bind:` from `binding_properties`, every public subpackage export discovered via `pkg.exports` + `import as ns`, every rune from `RUNES`, and directives (`transition:` / `animate:` / `use:` / `@attach` / `{@html}` / custom elements). Each gets a fixture, compiled and bundled like user code, then scanned. A row appears only when the fixture's floor exceeds the runtime floor. 3. Supplemental rules. A handful of APIs `web-features` doesn't catalogue (`getComputedStyle(...).zoom`, `box: 'device-pixel-content-box'`) are detected with the same type-aware walker via a small `register_extra_rules` list with inline justifications. 4. Ignore sets. `SAFE_TO_IGNORE` covers dataset bugs and feature-detected APIs with graceful fallbacks. `BEHAVIORAL_IGNORE` hides APIs reached only via specific user code from the headline (they still surface as conditional rows); staleness-checked, so CI fails if an entry no longer exists in the runtime. Resolves #18198. Provides an answer to the long-standing #558. ## Test plan - [ ] \`pnpm --filter svelte generate:browser-support\` regenerates the page idempotently - [ ] CI fails when a code change bumps the floor without regenerating the page - [ ] Page renders correctly on svelte.dev 🤖 Generated with [Claude Code](https://claude.com/claude-code) --------- Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Co-authored-by: Rich Harris <rich.harris@vercel.com>	3 weeks ago
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docs	docs: add auto-generated browser support page (#18276 )	3 weeks ago

docs: add auto-generated browser support page (#18276 )

## Summary

Adds a [Browser
support](https://github.com/MathiasWP/svelte/blob/document-pipeline-draft/documentation/docs/07-misc/05-browser-support.md)
page listing the minimum browser versions Svelte's runtime and compiler
output require. The page (headline floor + per-feature requirements) is
auto-generated by `packages/svelte/scripts/generate-browser-support.js`,
which scans the code Svelte actually ships against the
[web-features](https://github.com/web-platform-dx/web-features) Baseline
dataset and resolves results to concrete browser versions via
[baseline-browser-mapping](https://github.com/web-platform-dx/baseline-browser-mapping).
CI fails if a PR moves the floor without regenerating the page.

For 5.55.9 the floor is **Baseline 2020**: Chrome/Edge 87, Firefox 83,
Safari 14.

## How it works

1. **Headline floor.** Each runtime entry from `pkg.exports` is bundled
with rollup using production conditions, then walked with TypeScript's
compiler API + TypeChecker. The walker (`browser-support.detector.js`)
flags any web-features ID the runtime references; the highest Baseline
year among them is the floor.
2. **Per-feature requirements.** Every user-facing surface is enumerated
programmatically — every `bind:*` from `binding_properties`, every
public subpackage export discovered via `pkg.exports` + `import * as
ns`, every rune from `RUNES`, and directives (`transition:` / `animate:`
/ `use:` / `@attach` / `{@html}` / custom elements). Each gets a
fixture, compiled and bundled like user code, then scanned. A row
appears only when the fixture's floor exceeds the runtime floor.
3. **Supplemental rules.** A handful of APIs `web-features` doesn't
catalogue (`getComputedStyle(...).zoom`, `box:
'device-pixel-content-box'`) are detected with the same type-aware
walker via a small `register_extra_rules` list with inline
justifications.
4. **Ignore sets.** `SAFE_TO_IGNORE` covers dataset bugs and
feature-detected APIs with graceful fallbacks. `BEHAVIORAL_IGNORE` hides
APIs reached only via specific user code from the headline (they still
surface as conditional rows); staleness-checked, so CI fails if an entry
no longer exists in the runtime.

Resolves #18198. Provides an answer to the long-standing #558.

## Test plan

- [ ] \`pnpm --filter svelte generate:browser-support\` regenerates the
page idempotently
- [ ] CI fails when a code change bumps the floor without regenerating
the page
- [ ] Page renders correctly on svelte.dev

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>

docs

docs: add auto-generated browser support page (#18276 )