Convert build scripts to regular Flow syntax

jest/preprocessor.js

@@ -32,7 +32,7 @@ if (process.env.FBSOURCE_ENV === '1') {
   require('@fb-tools/babel-register');
 } else {
   // Register Babel to allow local packages to be loaded from source
-  require('../scripts/build/babel-register').registerForMonorepo();
+  require('../scripts/babel-register').registerForMonorepo();
 }
 
 const transformer = require('@react-native/metro-babel-transformer');

packages/community-cli-plugin/src/index.js

@@ -14,7 +14,7 @@ export type * from './index.flow';
 */
 
 if (!process.env.BUILD_EXCLUDE_BABEL_REGISTER) {
-  require('../../../scripts/build/babel-register').registerForMonorepo();
+  require('../../../scripts/babel-register').registerForMonorepo();
 }
 
 module.exports = require('./index.flow');

packages/core-cli-utils/src/index.js

@@ -14,7 +14,7 @@ export type * from './index.flow';
 */
 
 if (process.env.BUILD_EXCLUDE_BABEL_REGISTER == null) {
-  require('../../../scripts/build/babel-register').registerForMonorepo();
+  require('../../../scripts/babel-register').registerForMonorepo();
 }
 
 module.exports = require('./index.flow');

packages/core-cli-utils/src/public/version.js

@@ -14,7 +14,7 @@ export type * from './version.flow';
 */
 
 if (process.env.BUILD_EXCLUDE_BABEL_REGISTER == null) {
-  require('../../../../scripts/build/babel-register').registerForMonorepo();
+  require('../../../../scripts/babel-register').registerForMonorepo();
 }
 
 module.exports = require('./version.flow');

packages/dev-middleware/src/index.js

@@ -14,7 +14,7 @@ export type * from './index.flow';
 */
 
 if (!process.env.BUILD_EXCLUDE_BABEL_REGISTER) {
-  require('../../../scripts/build/babel-register').registerForMonorepo();
+  require('../../../scripts/babel-register').registerForMonorepo();
 }
 
 export * from './index.flow';

packages/helloworld/cli.js

@@ -32,7 +32,7 @@ function injectCoreCLIUtilsRuntimePatch() {
 
 if (process.env.BUILD_EXCLUDE_BABEL_REGISTER == null) {
   // $FlowFixMe[cannot-resolve-module]
-  require('../../scripts/build/babel-register').registerForMonorepo();
+  require('../../scripts/babel-register').registerForMonorepo();
 }
 
 injectCoreCLIUtilsRuntimePatch();

packages/metro-config/src/index.js

@@ -14,7 +14,7 @@ export type * from './index.flow';
 */
 
 if (!process.env.BUILD_EXCLUDE_BABEL_REGISTER) {
-  require('../../../scripts/build/babel-register').registerForMonorepo();
+  require('../../../scripts/babel-register').registerForMonorepo();
 }
 
 module.exports = require('./index.flow');

packages/react-native-fantom/config/metro-babel-transformer.js

@@ -9,5 +9,5 @@
 
 'use strict';
 
-require('../../../scripts/build/babel-register').registerForMonorepo();
+require('../../../scripts/babel-register').registerForMonorepo();
 module.exports = require('@react-native/metro-babel-transformer');

packages/react-native-fantom/runner/index.js

@@ -8,6 +8,6 @@
  * @oncall react_native
  */
 
-require('../../../scripts/build/babel-register').registerForMonorepo();
+require('../../../scripts/babel-register').registerForMonorepo();
 
 module.exports = require('./runner');

packages/react-native-fantom/runner/warmup/index.js

@@ -8,6 +8,6 @@
  * @oncall react_native
  */
 
-require('../../../../scripts/build/babel-register').registerForMonorepo();
+require('../../../../scripts/babel-register').registerForMonorepo();
 
 module.exports = require('./warmup');

packages/react-native/scripts/featureflags/index.js

@@ -8,7 +8,7 @@
  */
 
 if (require.main === module) {
-  require('../../../../scripts/build/babel-register').registerForMonorepo();
+  require('../../../../scripts/babel-register').registerForMonorepo();
 
   let command;
 

packages/rn-tester/cli.js

@@ -32,7 +32,7 @@ function injectCoreCLIUtilsRuntimePatch() {
 
 if (process.env.BUILD_EXCLUDE_BABEL_REGISTER == null) {
   // $FlowFixMe[cannot-resolve-module]
-  require('../../scripts/build/babel-register').registerForMonorepo();
+  require('../../scripts/babel-register').registerForMonorepo();
 }
 
 injectCoreCLIUtilsRuntimePatch();

scripts/build/babel-register.js → scripts/babel-register.js

@@ -9,9 +9,14 @@
  * @oncall react_native
  */
 
-const {PACKAGES_DIR, RN_INTEGRATION_TESTS_RUNNER_DIR} = require('../consts');
+const {
+  PACKAGES_DIR,
+  RN_INTEGRATION_TESTS_RUNNER_DIR,
+  SCRIPTS_DIR,
+} = require('./consts');
 
 let isRegisteredForMonorepo = false;
+let isRegisteredForScriptsDir = false;
 
 /**
  * Calling this function enables all Node.js packages to run from source when
@@ -21,9 +26,12 @@ let isRegisteredForMonorepo = false;
  * paths in "exports"), inside a special `if` condition that will be compiled
  * away on build.
  *
- *   if (!process.env.BUILD_EXCLUDE_BABEL_REGISTER) {
- *     require('../../../scripts/build/babel-register').registerForMonorepo();
- *   }
+ * ```js
+ * // Place in a package entry point
+ * if (!process.env.BUILD_EXCLUDE_BABEL_REGISTER) {
+ *   require('../../../scripts/babel-register').registerForMonorepo();
+ * }
+ * ```
  */
 function registerForMonorepo() {
   if (isRegisteredForMonorepo) {
@@ -43,4 +51,25 @@ function registerForMonorepo() {
   isRegisteredForMonorepo = true;
 }
 
-module.exports = {registerForMonorepo};
+/**
+ * Calling this function enables entry points under scripts/ to run from source.
+ *
+ * ```js
+ * // Place in a script entry point
+ * require('../babel-register').registerForScript();
+ * ```
+ */
+function registerForScript() {
+  if (isRegisteredForScriptsDir) {
+    return;
+  }
+
+  require('metro-babel-register')([SCRIPTS_DIR]);
+
+  isRegisteredForScriptsDir = true;
+}
+
+module.exports = {
+  registerForMonorepo,
+  registerForScript,
+};

scripts/build/babel/node.config.js

@@ -9,13 +9,11 @@
  * @oncall react_native
  */
 
-/*::
 import type {BabelCoreOptions} from '@babel/core';
-*/
 
 const TARGET_NODE_VERSION = '18';
 
-const config /*: BabelCoreOptions */ = {
+const config: BabelCoreOptions = {
   presets: [
     require.resolve('@babel/preset-flow'),
     [

scripts/build/build-types.js

@@ -9,6 +9,8 @@
  * @oncall react_native
  */
 
+require('../babel-register').registerForScript();
+
 const {PACKAGES_DIR, REPO_ROOT} = require('../consts');
 const translateSourceFile = require('./build-types/translateSourceFile');
 const chalk = require('chalk');
@@ -103,11 +105,11 @@ async function main() {
   );
 }
 
-function getPackageName(file /*: string */) /*: string */ {
+function getPackageName(file: string): string {
   return path.relative(PACKAGES_DIR, file).split(path.sep)[0];
 }
 
-function getBuildPath(file /*: string */) /*: string */ {
+function getBuildPath(file: string): string {
   const packageDir = path.join(PACKAGES_DIR, getPackageName(file));
 
   return path.join(
@@ -119,9 +121,9 @@ function getBuildPath(file /*: string */) /*: string */ {
   );
 }
 
-function ignoreShadowedFiles(files /*: Array<string> */) /*: Array<string> */ {
-  const shadowedPrefixes /*: Record<string, boolean> */ = {};
-  const result /*: Array<string> */ = [];
+function ignoreShadowedFiles(files: Array<string>): Array<string> {
+  const shadowedPrefixes: Record<string, boolean> = {};
+  const result: Array<string> = [];
 
   // Find all flow definition files that shadow other files
   for (const file of files) {

scripts/build/build-types/transforms/stripPrivateProperties.js

@@ -9,40 +9,38 @@
  * @oncall react_native
  */
 
-/*::
 import type {TransformVisitor} from 'hermes-transform';
-import type {TransformASTResult} from 'hermes-transform/dist/transform/transformAST';
 import type {ParseResult} from 'hermes-transform/dist/transform/parse';
- */
+import type {TransformASTResult} from 'hermes-transform/dist/transform/transformAST';
 
 const {transformAST} = require('hermes-transform/dist/transform/transformAST');
 
-const visitors /*: TransformVisitor */ = context => ({
-  ObjectTypeProperty(node) /*: void */ {
+const visitors: TransformVisitor = context => ({
+  ObjectTypeProperty(node): void {
     if (node.key.type === 'Identifier' && node.key.name.startsWith('_')) {
       context.removeNode(node);
     }
   },
-  Property(node) /*: void */ {
+  Property(node): void {
     if (node.key.type === 'Identifier' && node.key.name.startsWith('_')) {
       context.removeNode(node);
     }
   },
-  PropertyDefinition(node) /*: void */ {
+  PropertyDefinition(node): void {
     if (node.key.type === 'Identifier' && node.key.name.startsWith('_')) {
       context.removeNode(node);
     }
   },
-  MethodDefinition(node) /*: void */ {
+  MethodDefinition(node): void {
     if (node.key.type === 'Identifier' && node.key.name.startsWith('_')) {
       context.removeNode(node);
     }
   },
 });
 
 async function stripPrivateProperties(
-  source /*: ParseResult */,
-) /*: Promise<TransformASTResult> */ {
+  source: ParseResult,
+): Promise<TransformASTResult> {
   return transformAST(source, visitors);
 }
 

scripts/build/build-types/translateSourceFile.js

@@ -9,19 +9,15 @@
  * @oncall react_native
  */
 
-/*::
 import type {ParseResult} from 'hermes-transform/dist/transform/parse';
 import type {TransformASTResult} from 'hermes-transform/dist/transform/transformAST';
-*/
 
 const translate = require('flow-api-translator');
 const {parse, print} = require('hermes-transform');
 
-/*::
-type TransformFn = (ParseResult) => Promise<TransformASTResult>;
-*/
+type TransformFn = ParseResult => Promise<TransformASTResult>;
 
-const preTransforms /*: Array<TransformFn> */ = [
+const preTransforms: Array<TransformFn> = [
   require('./transforms/stripPrivateProperties'),
 ];
 const prettierOptions = {parser: 'babel'};
@@ -32,9 +28,7 @@ const prettierOptions = {parser: 'babel'};
  * This uses [flow-api-translator](https://www.npmjs.com/package/flow-api-translator),
  * and applies extra transformations such as stripping private properties.
  */
-async function translateSourceFile(
-  source /*: string */,
-) /*: Promise<string> */ {
+async function translateSourceFile(source: string): Promise<string> {
   // Parse Flow source
   const parsed = await parse(source);
 
@@ -49,9 +43,9 @@ async function translateSourceFile(
 }
 
 async function applyTransforms(
-  source /*: ParseResult */,
-  transforms /*: $ReadOnlyArray<TransformFn> */,
-) /*: Promise<ParseResult> */ {
+  source: ParseResult,
+  transforms: $ReadOnlyArray<TransformFn>,
+): Promise<ParseResult> {
   return transforms.reduce((input, transform) => {
     return input.then(async result => {
       const transformed = await transform(result);

scripts/build/build.js

@@ -9,6 +9,8 @@
  * @oncall react_native
  */
 
+require('../babel-register').registerForScript();
+
 const {PACKAGES_DIR, REPO_ROOT} = require('../consts');
 const {
   buildConfig,

scripts/build/clean.js

@@ -9,6 +9,8 @@
  * @oncall react_native
  */
 
+require('../babel-register').registerForScript();
+
 const {BUILD_DIR, PACKAGES_DIR} = require('./build');
 const {buildConfig} = require('./config');
 const fs = require('fs');

scripts/build/config.js

@@ -9,13 +9,12 @@
  * @oncall react_native
  */
 
-/*::
+require('../babel-register').registerForScript();
+
 import type {BabelCoreOptions} from '@babel/core';
-*/
 
 const {ModuleResolutionKind} = require('typescript');
 
-/*::
 export type BuildOptions = $ReadOnly<{
   // The target runtime to compile for.
   target: 'node',
@@ -31,7 +30,6 @@ export type BuildConfig = $ReadOnly<{
   // The packages to include for build and their build options.
   packages: $ReadOnly<{[packageName: string]: BuildOptions}>,
 }>;
-*/
 
 /**
  * - BUILD CONFIG -
@@ -40,7 +38,7 @@ export type BuildConfig = $ReadOnly<{
  * setup. These must use a consistent package structure and (today) target
  * Node.js packages only.
  */
-const buildConfig /*: BuildConfig */ = {
+const buildConfig: BuildConfig = {
   /* eslint sort-keys: "error" */
   packages: {
     'community-cli-plugin': {
@@ -67,17 +65,17 @@ const defaultBuildOptions = {
 };
 
 function getBuildOptions(
-  packageName /*: $Keys<BuildConfig['packages']> */,
-) /*: Required<BuildOptions> */ {
+  packageName: $Keys<BuildConfig['packages']>,
+): Required<BuildOptions> {
   return {
     ...defaultBuildOptions,
     ...buildConfig.packages[packageName],
   };
 }
 
 function getBabelConfig(
-  packageName /*: $Keys<BuildConfig['packages']> */,
-) /*: BabelCoreOptions */ {
+  packageName: $Keys<BuildConfig['packages']>,
+): BabelCoreOptions {
   const {target} = getBuildOptions(packageName);
 
   switch (target) {
@@ -87,8 +85,8 @@ function getBabelConfig(
 }
 
 function getTypeScriptCompilerOptions(
-  packageName /*: $Keys<BuildConfig['packages']> */,
-) /*: Object */ {
+  packageName: $Keys<BuildConfig['packages']>,
+): Object {
   const {target} = getBuildOptions(packageName);
 
   switch (target) {