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Alex Hunt a978d343a6 Add auto-generation of TypeScript definitions on build (#38990)
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/38990

This PR adds auto-generation of Typescript definitions from Flow source code for packages using the shared monorepo build setup (https://github.com/facebook/react-native/pull/38718).

Today, these are the following Node.js packages:

- `packages/community-cli-plugin`
- `packages/dev-middleware` (⬅️ `emitTypeScriptDefs` enabled)

This also improves emitted Flow definitions (`.js.flow`), by using [`flow-api-translator`](https://www.npmjs.com/package/flow-api-translator) to strip implementations.

**All changes**

- Include `flow-api-translator` and configure this to emit type definitions as part of `yarn build`.
    - Add translation from Flow source to TypeScript definitions (`.d.ts`) adjacent to each built file.
    - Improve emitted Flow definitions (`.js.flow`), by using `flow-api-translator` to strip implementations (previously, source files were copied). The Flow and TS defs now mirror each other.
-  Add `emitFlowDefs` and `emitTypeScriptDefs` options to build config to configure the above.
- Integrate TypeScript compiler to perform program validation on emitted `.d.ts` files.
     - This is based on this guide: https://github.com/microsoft/TypeScript-wiki/blob/main/Using-the-Compiler-API.md#a-minimal-compiler.
- Throw an exception on the `rewritePackageExports` step if a package does not define an `"exports"` field.
- Add minimal `flow-typed` definitions for `typescript` 😄.

**Notes on [`flow-api-translator`](https://www.npmjs.com/package/flow-api-translator)**

This project is experimental but is in a more mature state than when we evaluated it earlier in 2023.
- It's now possible to run this tool on our new Node.js packages, since they are exclusively authored using `import`/`export` syntax (a requirement of the tool).
- As a safety net, we run the TypeScript compiler against the generated program, which will fail the build.

Changelog: [Internal]

Reviewed By: robhogan

Differential Revision: D48312463

fbshipit-source-id: 817edb35f911f52fa987946f2d8fc1a319078c9d
2023-08-14 12:12:10 -07:00

100 lines
2.2 KiB
JavaScript

/**
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @flow
* @format
* @oncall react_native
*/
/*::
import type {BabelCoreOptions} from '@babel/core';
*/
const {ModuleResolutionKind} = require('typescript');
/*::
export type BuildOptions = $ReadOnly<{
// The target runtime to compile for.
target: 'node',
// Whether to emit Flow definition files (.js.flow) (default: true).
emitFlowDefs?: boolean,
// Whether to emit TypeScript definition files (.d.ts) (default: false).
emitTypeScriptDefs?: boolean,
}>;
export type BuildConfig = $ReadOnly<{
// The packages to include for build and their build options.
packages: $ReadOnly<{[packageName: string]: BuildOptions}>,
}>;
*/
/**
* - BUILD CONFIG -
*
* Add packages here to configure them as part of the monorepo `yarn build`
* setup. These must use a consistent package structure and (today) target
* Node.js packages only.
*/
const buildConfig /*: BuildConfig */ = {
packages: {
'community-cli-plugin': {
target: 'node',
},
'dev-middleware': {
target: 'node',
emitTypeScriptDefs: true,
},
},
};
const defaultBuildOptions = {
emitFlowDefs: true,
emitTypeScriptDefs: false,
};
function getBuildOptions(
packageName /*: $Keys<BuildConfig['packages']> */,
) /*: Required<BuildOptions> */ {
return {
...defaultBuildOptions,
...buildConfig.packages[packageName],
};
}
function getBabelConfig(
packageName /*: $Keys<BuildConfig['packages']> */,
) /*: BabelCoreOptions */ {
const {target} = getBuildOptions(packageName);
switch (target) {
case 'node':
return require('./babel/node.config.js');
}
}
function getTypeScriptCompilerOptions(
packageName /*: $Keys<BuildConfig['packages']> */,
) /*: Object */ {
const {target} = getBuildOptions(packageName);
switch (target) {
case 'node':
return {
...require('@tsconfig/node18/tsconfig.json').compilerOptions,
moduleResolution: ModuleResolutionKind.NodeJs,
};
}
}
module.exports = {
buildConfig,
getBabelConfig,
getBuildOptions,
getTypeScriptCompilerOptions,
};