Rubén Norte
833144fcec
Summary: Pull Request resolved: https://github.com/facebook/react-native/pull/56998 Reverts the recent Flow syntax codemods applied across `packages/`, `private/`, and `scripts/` in react-native-github. Specifically restores the previous form for: - `+T` / `+Instance` style variance annotations on generic type parameters that had been converted to the newer `out T` / `in T` keyword form. - `+field:` covariant object/interface properties that had been converted to the `readonly field:` modifier form. - `+[K in keyof T]:` mapped-type covariance that had been converted to `readonly [K in keyof T]:`. These are purely Flow type-annotation changes with no runtime behavior impact, restoring the form that the rest of the toolchain (in particular Fantom) already supports. Changelog: [Internal] Reviewed By: christophpurrer Differential Revision: D106813102 fbshipit-source-id: 6bf915d530e130eba9c9d96a2b6c3dc8853594d1
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.