Add build script to react-native-babel-transformer

Summary:
This diff adds build script and 'prepare' hook to `react-native-babel-transformer`. The script is effectively is a copy-paste from `react-native-codegen`, we'll deduplicate them in the future.

Changelog: [Internal] - Add build script to react-native-babel-transformer

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Differential Revision: https://internalfb.com/D47006627

fbshipit-source-id: 7b05d98759d8554f46e57684db4247368a78e0d4

packages/react-native-babel-transformer/.babelrc

@@ -0,0 +1,12 @@
+{
+  "plugins": [
+    "@babel/plugin-proposal-object-rest-spread",
+    "@babel/plugin-transform-async-to-generator",
+    "@babel/plugin-transform-destructuring",
+    "@babel/plugin-transform-flow-strip-types",
+    "@babel/plugin-syntax-dynamic-import",
+    "@babel/plugin-proposal-class-properties",
+    "@babel/plugin-proposal-nullish-coalescing-operator",
+    "@babel/plugin-proposal-optional-chaining"
+  ]
+}

packages/react-native-babel-transformer/.prettierrc

@@ -0,0 +1,8 @@
+{
+  "arrowParens": "avoid",
+  "bracketSameLine": true,
+  "bracketSpacing": false,
+  "requirePragma": true,
+  "singleQuote": true,
+  "trailingComma": "all"
+}

packages/react-native-babel-transformer/package.json

@@ -8,8 +8,12 @@
     "url": "[email protected]:facebook/metro.git"
   },
   "scripts": {
-    "prepare-release": "test -d build && rm -rf src.real && mv src src.real && mv build src",
-    "cleanup-release": "test ! -e build && mv src build && mv src.real src"
+    "prepare-release": "test -d lib && mv src src.real && mv lib src",
+    "cleanup-release": "test ! -e lib && mv src lib && mv src.real src && rimraf lib",
+    "build-clean": "rimraf build && rimraf src.real",
+    "build": " node scripts/build.js --verbose",
+    "prepare": "yarn run build-clean && yarn run build && yarn run prepare-release",
+    "postpublish": "yarn run cleanup-release"
   },
   "keywords": [
     "transformer",
@@ -24,6 +28,24 @@
     "metro-react-native-babel-preset": "0.76.7",
     "nullthrows": "^1.1.1"
   },
+  "devDependencies": {
+    "@babel/plugin-proposal-class-properties": "^7.18.0",
+    "@babel/plugin-proposal-nullish-coalescing-operator": "^7.18.0",
+    "@babel/plugin-proposal-object-rest-spread": "^7.20.0",
+    "@babel/plugin-proposal-optional-chaining": "^7.20.0",
+    "@babel/plugin-syntax-dynamic-import": "^7.8.0",
+    "@babel/plugin-transform-async-to-generator": "^7.20.0",
+    "@babel/plugin-transform-destructuring": "^7.20.0",
+    "@babel/plugin-transform-flow-strip-types": "^7.20.0",
+    "@babel/preset-env": "^7.20.0",
+    "chalk": "^4.0.0",
+    "glob": "^7.1.1",
+    "invariant": "^2.2.4",
+    "micromatch": "^4.0.4",
+    "mkdirp": "^0.5.1",
+    "prettier": "2.8.8",
+    "rimraf": "^3.0.2"
+  },
   "peerDependencies": {
     "@babel/core": "*"
   },

packages/react-native-babel-transformer/scripts/build.js

@@ -0,0 +1,114 @@
+/**
+ * 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.
+ *
+ * @format
+ */
+
+/**
+ * script to build (transpile) files.
+ *
+ * Based off of the build script from Metro, and tweaked to run in just one
+ * package instead of in a monorepo. Just run `build.js` and the JS files in
+ * `src/` will be built in `lib/`, and the original source files will be copied
+ * over as `Example.js.flow`, so consumers of this module can still make use of
+ * type checking.
+ *
+ * Call this script with the `--verbose` flag to show the full output of this
+ * script.
+ */
+
+'use strict';
+
+const babel = require('@babel/core');
+const chalk = require('chalk');
+const fs = require('fs');
+const glob = require('glob');
+const micromatch = require('micromatch');
+const mkdirp = require('mkdirp');
+const path = require('path');
+const prettier = require('prettier');
+const prettierConfig = JSON.parse(
+  fs.readFileSync(path.resolve(__dirname, '..', '.prettierrc'), 'utf8'),
+);
+
+const SRC_DIR = 'src';
+const BUILD_DIR = 'lib';
+const JS_FILES_PATTERN = '**/*.js';
+const IGNORE_PATTERN = '**/__tests__/**';
+const PACKAGE_DIR = path.resolve(__dirname, '../');
+
+const fixedWidth = str => {
+  const WIDTH = 80;
+  const strs = str.match(new RegExp(`(.{1,${WIDTH}})`, 'g')) || [str];
+  let lastString = strs[strs.length - 1];
+  if (lastString.length < WIDTH) {
+    lastString += Array(WIDTH - lastString.length).join(chalk.dim('.'));
+  }
+  return strs.slice(0, -1).concat(lastString).join('\n');
+};
+
+function getBuildPath(file, buildFolder) {
+  const pkgSrcPath = path.resolve(PACKAGE_DIR, SRC_DIR);
+  const pkgBuildPath = path.resolve(PACKAGE_DIR, BUILD_DIR);
+  const relativeToSrcPath = path.relative(pkgSrcPath, file);
+  return path.resolve(pkgBuildPath, relativeToSrcPath);
+}
+
+function buildFile(file, silent) {
+  const destPath = getBuildPath(file, BUILD_DIR);
+
+  mkdirp.sync(path.dirname(destPath));
+  if (micromatch.isMatch(file, IGNORE_PATTERN)) {
+    silent ||
+      process.stdout.write(
+        chalk.dim('  \u2022 ') +
+          path.relative(PACKAGE_DIR, file) +
+          ' (ignore)\n',
+      );
+  } else if (!micromatch.isMatch(file, JS_FILES_PATTERN)) {
+    fs.createReadStream(file).pipe(fs.createWriteStream(destPath));
+    silent ||
+      process.stdout.write(
+        chalk.red('  \u2022 ') +
+          path.relative(PACKAGE_DIR, file) +
+          chalk.red(' \u21D2 ') +
+          path.relative(PACKAGE_DIR, destPath) +
+          ' (copy)' +
+          '\n',
+      );
+  } else {
+    const transformed = prettier.format(
+      babel.transformFileSync(file, {}).code,
+      {
+        ...prettierConfig,
+        parser: 'babel',
+      },
+    );
+    fs.writeFileSync(destPath, transformed);
+    const source = fs.readFileSync(file).toString('utf-8');
+    if (/@flow/.test(source)) {
+      fs.createReadStream(file).pipe(fs.createWriteStream(destPath + '.flow'));
+    }
+    silent ||
+      process.stdout.write(
+        chalk.green('  \u2022 ') +
+          path.relative(PACKAGE_DIR, file) +
+          chalk.green(' \u21D2 ') +
+          path.relative(PACKAGE_DIR, destPath) +
+          '\n',
+      );
+  }
+}
+
+const srcDir = path.resolve(__dirname, '..', SRC_DIR);
+const pattern = path.resolve(srcDir, '**/*');
+const files = glob.sync(pattern, {nodir: true});
+
+process.stdout.write(fixedWidth(`${path.basename(PACKAGE_DIR)}\n`));
+
+files.forEach(file => buildFile(file, !process.argv.includes('--verbose')));
+
+process.stdout.write(`[  ${chalk.green('OK')}  ]\n`);