Replace deprecated Rollup option 'legacy' with custom plugin.

scripts/babel/__tests__/remove-getters-test.js

@@ -0,0 +1,66 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+'use strict';
+
+const babel = require('babel-core');
+const removeGetters = require('../remove-getters');
+
+function transform(input) {
+  return babel.transform(input, {
+    plugins: [removeGetters],
+  }).code;
+}
+
+function compare(input, output) {
+  const compiled = transform(input);
+  expect(compiled).toEqual(output);
+}
+
+describe('remove-getters', () => {
+  it('should remove getters', () => {
+    compare(
+      `const object = {
+  get prop() {
+    return variable;
+  }
+};`,
+      `const object = {
+  prop: variable
+};`
+    );
+  });
+
+  it('should not remove other methods or properties', () => {
+    compare(
+      `const object = {
+  prop: 'foo',
+  method() {
+    return 'bar';
+  }
+};`,
+      `const object = {
+  prop: 'foo',
+  method() {
+    return 'bar';
+  }
+};`
+    );
+  });
+
+  it('should throw when finding getters with a different syntax from the ones generated by Rollup', () => {
+    expect(() => {
+      transform(
+        `const object = {
+  get prop() {
+    const foo = 'foo';
+    return foo;
+  }
+};`
+      );
+    }).toThrow();
+  });
+});

scripts/babel/remove-getters.js

@@ -0,0 +1,54 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+'use strict';
+
+module.exports = ({types: t}) => {
+  return {
+    visitor: {
+      ObjectMethod: path => {
+        // Turns this code:
+        //
+        // get prop() {
+        //   return variable;
+        // }
+        //
+        // into this:
+        //
+        // prop: variable;
+        if (path.node.kind !== 'get') {
+          return;
+        }
+
+        const keyNode = path.node.key;
+        const isValidKey = t.isIdentifier(keyNode);
+        if (!isValidKey) {
+          throw path.buildCodeFrameError(
+            'Getter key format not supported. Expected identifier.'
+          );
+        }
+
+        const bodyNode = path.node.body;
+        const isValidBody =
+          bodyNode.body.length === 1 &&
+          t.isReturnStatement(bodyNode.body[0]) &&
+          t.isIdentifier(bodyNode.body[0].argument);
+        if (!isValidBody) {
+          throw path.buildCodeFrameError(
+            'Getter body format not supported. Expected return of identifier.'
+          );
+        }
+
+        const prop = keyNode.name;
+        const variable = bodyNode.body[0].argument.name;
+
+        path.replaceWith(
+          t.objectProperty(t.identifier(prop), t.identifier(variable))
+        );
+      },
+    },
+  };
+};

scripts/rollup/build.js

@@ -2,6 +2,7 @@
 
 const {rollup} = require('rollup');
 const babel = require('rollup-plugin-babel');
+const babelCore = require('babel-core');
 const closure = require('./plugins/closure-plugin');
 const commonjs = require('rollup-plugin-commonjs');
 const prettier = require('rollup-plugin-prettier');
@@ -335,6 +336,23 @@ function getPlugins(
           .replace(/require\(['"]react-is['"]\)/g, "require('ReactIs')");
       },
     },
+    isFBBundle && {
+      transformBundle(source) {
+        // Run a final Babel pass after Rollup bundle.
+        const babelOptions = {
+          ast: false,
+          babelrc: false,
+          compact: false,
+          plugins: [
+            // This is needed because Rollup outputs getters, but we can't use
+            // getters in www.
+            require('../babel/remove-getters'),
+          ],
+        };
+        const result = babelCore.transform(source, babelOptions);
+        return result.code;
+      },
+    },
     // Apply dead code elimination and/or minification.
     isProduction &&
       closure(
@@ -420,11 +438,11 @@ async function createBundle(bundle, bundleType) {
   const packageName = Packaging.getPackageName(bundle.entry);
 
   let resolvedEntry = require.resolve(bundle.entry);
-  if (
+  const isFBBundle =
     bundleType === FB_WWW_DEV ||
     bundleType === FB_WWW_PROD ||
-    bundleType === FB_WWW_PROFILING
-  ) {
+    bundleType === FB_WWW_PROFILING;
+  if (isFBBundle) {
     const resolvedFBEntry = resolvedEntry.replace('.js', '.fb.js');
     if (fs.existsSync(resolvedFBEntry)) {
       resolvedEntry = resolvedFBEntry;
@@ -470,11 +488,6 @@ async function createBundle(bundle, bundleType) {
       bundle.moduleType,
       bundle.modulesToStub
     ),
-    // We can't use getters in www.
-    legacy:
-      bundleType === FB_WWW_DEV ||
-      bundleType === FB_WWW_PROD ||
-      bundleType === FB_WWW_PROFILING,
   };
   const [mainOutputPath, ...otherOutputPaths] = Packaging.getBundleOutputPaths(
     bundleType,