Alex Hunt
642273788b
Summary: Pull Request resolved: https://github.com/react/react-native/pull/57389 **Context** Strict TypeScript API readiness: High quality inline docs should reach users via TypeScript in their IDEs. **This diff** Prior iterations of our Flow → TS translation stack dropped doc comments for default-exported values, and/or identifiers which change shape after type transformation (e.g. Flow `component` syntax), meaning many root APIs (`View`, `ScrollView`, `Pressable`, and others) showed no documentation on hover. This diff extends the existing `reattachDocComments` transform to handle doc comment repositioning (suitable for the TS lang server) from a greater set of source positions: - the exported declaration - a `.displayName` assignment - a HOC-wrapped inner component - a renamed wrapper's public-named component - a `declare const` / `declare export default typeof X` stub **Impact** (With the source code JSDoc improvements earlier in this stack.) | Before (legacy types) | After (Strict API) | | -- | | {F1991869487} | {F1991869472} | | ⚠️ No inline docs for many symbols | ✅ New, detailed inline docs reach the TS server 🎉 | Changelog: [General][Fixed] - Preserve doc comments on root API symbols in the generated TypeScript types Reviewed By: rubennorte Differential Revision: D109316361 fbshipit-source-id: 8a83455fcf317f355bd7c5a67712d322248d8b00
scripts/js-api
TypeScript build pipeline for React Native's JavaScript API.
Overview
yarn build-types is a custom build pipeline for translating React Native's Flow source code to TypeScript.
Specifically, it reduces the runtime JavaScript API of react-native into two outputs:
- Generated TypeScript types
Public user types for react-native, shipped to npm
packages/react-native/types_generated/ - Public API snapshot
Snapshot file of the public API shape, used by maintainers
packages/react-native/ReactNativeApi.d.ts
Dependencies
yarn build-types makes use of the following dependencies, composed with other pre/post transformation steps and dependency resolution.
- Flow → TypeScript conversion: flow-api-translator
- TypeScript → (initial) API rollup: @microsoft/api-extractor
Usage
Build generated types + API snapshot
Maintainers should run this script whenever making intentional API changes.
# Build types + API snapshot
yarn build-types [--validate]
# Build types without API snapshot
yarn build-types --skip-snapshot
Diff API snapshot compatibility
This script is run by CI to compare changes to ReactNativeApi.d.ts between commits.
# Compare two versions of the API snapshot
yarn js-api-diff <before.d.ts> <after.d.ts>
{
"result": "BREAKING",
"changedApis": [
"ViewStyle"
]
}
Configuration
Sparse configuration options are defined and documented in scripts/js-api/config.js.
About the two output formats
Generated TypeScript types
types_generated/
Directory providing TypeScript user types for the react-native package, distributed via npm.
- Gitignored.
- Scoped to the
index.d.tsentry point viapackage.json#exports. - Preserves
unstable_andexperimental_APIs. - Preserves doc comments.
- Preserves source file names (for go to definition).
Public API snapshot
ReactNativeApi.d.ts
Provides a human-readable, maintainable reference of the React Native's public JavaScript API, optimized for developers and diff tooling.
- Committed to the repo.
- Strips
unstable_andexperimental_APIs. - Strips doc comments.
- Strips source file names (types are merged into a single program).
- Versions exported APIs with an 8 char SHA hash, which will be updated when any input type dependencies change shape.