From 23e3503dde5f914f3e642ef214f508d0a699851d Mon Sep 17 00:00:00 2001
From: James Ide <ide@expo.io>
Date: Tue, 12 Mar 2019 20:29:31 -0700
Subject: [PATCH] Default to lazy requires for all public RN exports (#362)

Summary:
**Summary**

This commit changes `metro-react-native-babel-preset` to emit lazy `require` calls for all of RN's public exports. This is so that we can move RN to use ES import/export, which syntactically have no lazy version, while preserving the lazy behavior we have today by default.

If the developer specifies `lazyImportExportTransform: true`, all imports/exports will be lazy including RN's public exports, so they will remain lazy. (Also, this PR allows developers to specify non-boolean values for `lazyImportExportTransform` e.g. an array of whitelisted paths.)

Note: this commit must land and be published before RN can use ESM since the iOS E2E tests depend on the current lazy `require` calls.

See the draft PR for RN here: https://github.com/facebook/react-native/pull/23591

**Test plan**

Used this module inside of the RN E2E iOS tests and loaded the bundle successfully. Also used it in RNTester.
Pull Request resolved: https://github.com/facebook/metro/pull/362

Differential Revision: D14434999

Pulled By: cpojer

fbshipit-source-id: d280a8216c6e1c6604e8fea508f5a48f4c1c071b
---
 .../src/configs/lazy-imports.js               | 115 ++++++++++++++++++
 .../src/configs/main.js                       |   7 +-
 2 files changed, 121 insertions(+), 1 deletion(-)
 create mode 100644 packages/metro-react-native-babel-preset/src/configs/lazy-imports.js

diff --git a/packages/metro-react-native-babel-preset/src/configs/lazy-imports.js b/packages/metro-react-native-babel-preset/src/configs/lazy-imports.js
new file mode 100644
index 0000000000..6cbdf119f2
--- /dev/null
+++ b/packages/metro-react-native-babel-preset/src/configs/lazy-imports.js
@@ -0,0 +1,115 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * This is the set of modules that React Native publicly exports and that we
+ * want to require lazily. Keep this list in sync with
+ * Libraries/react-native/react-native-implementation.js (though having extra
+ * entries here is fairly harmless).
+
+ * @format
+ */
+'use strict';
+
+module.exports = new Set([
+  'AccessibilityInfo',
+  'ActivityIndicator',
+  'ReactNativeART',
+  'Button',
+  'CheckBox',
+  'DatePickerIOS',
+  'DrawerLayoutAndroid',
+  'FlatList',
+  'Image',
+  'ImageBackground',
+  'ImageEditor',
+  'ImageStore',
+  'InputAccessoryView',
+  'KeyboardAvoidingView',
+  'ListView',
+  'MaskedViewIOS',
+  'Modal',
+  'Picker',
+  'PickerIOS',
+  'ProgressBarAndroid',
+  'ProgressViewIOS',
+  'SafeAreaView',
+  'ScrollView',
+  'SectionList',
+  'SegmentedControlIOS',
+  'Slider',
+  'Switch',
+  'RefreshControl',
+  'StatusBar',
+  'SwipeableFlatList',
+  'SwipeableListView',
+  'Text',
+  'TextInput',
+  'ToolbarAndroid',
+  'Touchable',
+  'TouchableHighlight',
+  'TouchableNativeFeedback',
+  'TouchableOpacity',
+  'TouchableWithoutFeedback',
+  'View',
+  'ViewPagerAndroid',
+  'VirtualizedList',
+  'WebView',
+
+  // APIs
+  'ActionSheetIOS',
+  'Alert',
+  'Animated',
+  'AppRegistry',
+  'AppState',
+  'AsyncStorage',
+  'BackHandler',
+  'CameraRoll',
+  'Clipboard',
+  'DatePickerAndroid',
+  'DeviceInfo',
+  'Dimensions',
+  'Easing',
+  'ReactNative',
+  'I18nManager',
+  'ImagePickerIOS',
+  'InteractionManager',
+  'Keyboard',
+  'LayoutAnimation',
+  'Linking',
+  'NativeEventEmitter',
+  'NetInfo',
+  'PanResponder',
+  'PermissionsAndroid',
+  'PixelRatio',
+  'PushNotificationIOS',
+  'Settings',
+  'Share',
+  'StatusBarIOS',
+  'StyleSheet',
+  'Systrace',
+  'TimePickerAndroid',
+  'ToastAndroid',
+  'TVEventHandler',
+  'UIManager',
+  'ReactNative',
+  'UTFSequence',
+  'Vibration',
+  'YellowBox',
+
+  // Plugins
+  'RCTDeviceEventEmitter',
+  'RCTNativeAppEventEmitter',
+  'NativeModules',
+  'Platform',
+  'processColor',
+  'requireNativeComponent',
+
+  // Prop Types
+  'DeprecatedColorPropType',
+  'DeprecatedEdgeInsetsPropType',
+  'DeprecatedPointPropType',
+  'DeprecatedViewPropTypes',
+]);
diff --git a/packages/metro-react-native-babel-preset/src/configs/main.js b/packages/metro-react-native-babel-preset/src/configs/main.js
index b1d3beebdf..8600a756aa 100644
--- a/packages/metro-react-native-babel-preset/src/configs/main.js
+++ b/packages/metro-react-native-babel-preset/src/configs/main.js
@@ -9,6 +9,8 @@
 
 'use strict';
 
+const lazyImports = require('./lazy-imports');
+
 function isTypeScriptSource(fileName) {
   return !!fileName && fileName.endsWith('.ts');
 }
@@ -93,7 +95,10 @@ const getPreset = (src, options) => {
         {
           strict: false,
           strictMode: false, // prevent "use strict" injections
-          lazy: !!(options && options.lazyImportExportTransform),
+          lazy:
+            options && options.lazyImportExportTransform != null
+              ? options.lazyImportExportTransform
+              : importSpecifier => lazyImports.has(importSpecifier),
           allowTopLevelThis: true, // dont rewrite global `this` -> `undefined`
         },
       ],