Extract some platform related code to a separate file

Reviewed By: davidaurelio

Differential Revision: D6491060

fbshipit-source-id: e8d040495b549e1925932b4ded4b44dd1f81fff6

packages/metro/src/JSTransformer/worker/inline-platform.js

@@ -0,0 +1,104 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @flow
+ * @format
+ */
+
+'use strict';
+
+const babel = require('babel-core');
+
+const t = babel.types;
+const importMap = new Map([['ReactNative', 'react-native']]);
+
+const isPlatformOS = (node: any, scope: any, isWrappedModule: boolean) =>
+  t.isIdentifier(node.property, {name: 'OS'}) &&
+  isImportOrGlobal(node.object, scope, [{name: 'Platform'}], isWrappedModule);
+
+const isReactPlatformOS = (node: any, scope: any, isWrappedModule: boolean) =>
+  t.isIdentifier(node.property, {name: 'OS'}) &&
+  t.isMemberExpression(node.object) &&
+  t.isIdentifier(node.object.property, {name: 'Platform'}) &&
+  isImportOrGlobal(
+    node.object.object,
+    scope,
+    [{name: 'React'}, {name: 'ReactNative'}],
+    isWrappedModule,
+  );
+
+const isPlatformSelect = (node: any, scope: any, isWrappedModule: boolean) =>
+  t.isMemberExpression(node.callee) &&
+  t.isIdentifier(node.callee.object, {name: 'Platform'}) &&
+  t.isIdentifier(node.callee.property, {name: 'select'}) &&
+  isImportOrGlobal(
+    node.callee.object,
+    scope,
+    [{name: 'Platform'}],
+    isWrappedModule,
+  );
+
+const isReactPlatformSelect = (
+  node: any,
+  scope: any,
+  isWrappedModule: boolean,
+) =>
+  t.isMemberExpression(node.callee) &&
+  t.isIdentifier(node.callee.property, {name: 'select'}) &&
+  t.isMemberExpression(node.callee.object) &&
+  t.isIdentifier(node.callee.object.property, {name: 'Platform'}) &&
+  isImportOrGlobal(
+    node.callee.object.object,
+    scope,
+    [{name: 'React'}, {name: 'ReactNative'}],
+    isWrappedModule,
+  );
+
+const isGlobal = binding => !binding;
+
+const isRequireCall = (node, dependencyId, scope) =>
+  t.isCallExpression(node) &&
+  t.isIdentifier(node.callee, {name: 'require'}) &&
+  checkRequireArgs(node.arguments, dependencyId);
+
+const isImport = (node, scope, patterns) =>
+  patterns.some(pattern => {
+    const importName = importMap.get(pattern.name) || pattern.name;
+    return isRequireCall(node, importName, scope);
+  });
+
+const isImportOrGlobal = (node, scope, patterns, isWrappedModule) => {
+  const identifier = patterns.find(pattern => t.isIdentifier(node, pattern));
+  return (
+    (identifier &&
+      isToplevelBinding(scope.getBinding(identifier.name), isWrappedModule)) ||
+    isImport(node, scope, patterns)
+  );
+};
+
+const checkRequireArgs = (args, dependencyId) => {
+  const pattern = t.stringLiteral(dependencyId);
+  return (
+    t.isStringLiteral(args[0], pattern) ||
+    (t.isMemberExpression(args[0]) &&
+      t.isNumericLiteral(args[0].property) &&
+      t.isStringLiteral(args[1], pattern))
+  );
+};
+
+const isToplevelBinding = (binding, isWrappedModule) =>
+  isGlobal(binding) ||
+  !binding.scope.parent ||
+  (isWrappedModule && !binding.scope.parent.parent);
+
+module.exports = {
+  isPlatformOS,
+  isReactPlatformOS,
+  isPlatformSelect,
+  isReactPlatformSelect,
+};

packages/metro/src/JSTransformer/worker/inline.js

@@ -13,26 +13,18 @@
 'use strict';
 
 const babel = require('babel-core');
+const inlinePlatform = require('./inline-platform');
 const invariant = require('fbjs/lib/invariant');
 
 import type {Ast, SourceMap as MappingsMap} from 'babel-core';
 const t = babel.types;
 
-const React = {name: 'React'};
-const ReactNative = {name: 'ReactNative'};
-const platform = {name: 'Platform'};
-const os = {name: 'OS'};
-const select = {name: 'select'};
-const requirePattern = {name: 'require'};
-
 const env = {name: 'env'};
 const nodeEnv = {name: 'NODE_ENV'};
 const processId = {name: 'process'};
 
 const dev = {name: '__DEV__'};
 
-const importMap = new Map([['ReactNative', 'react-native']]);
-
 const isGlobal = binding => !binding;
 
 const isFlowDeclared = binding => t.isDeclareVariable(binding.path);
@@ -40,49 +32,9 @@ const isFlowDeclared = binding => t.isDeclareVariable(binding.path);
 const isGlobalOrFlowDeclared = binding =>
   isGlobal(binding) || isFlowDeclared(binding);
 
-const isToplevelBinding = (binding, isWrappedModule) =>
-  isGlobal(binding) ||
-  !binding.scope.parent ||
-  (isWrappedModule && !binding.scope.parent.parent);
-
-const isRequireCall = (node, dependencyId, scope) =>
-  t.isCallExpression(node) &&
-  t.isIdentifier(node.callee, requirePattern) &&
-  checkRequireArgs(node.arguments, dependencyId);
-
-const isImport = (node, scope, patterns) =>
-  patterns.some(pattern => {
-    const importName = importMap.get(pattern.name) || pattern.name;
-    return isRequireCall(node, importName, scope);
-  });
-
-function isImportOrGlobal(node, scope, patterns, isWrappedModule) {
-  const identifier = patterns.find(pattern => t.isIdentifier(node, pattern));
-  return (
-    (identifier &&
-      isToplevelBinding(scope.getBinding(identifier.name), isWrappedModule)) ||
-    isImport(node, scope, patterns)
-  );
-}
-
 const isLeftHandSideOfAssignmentExpression = (node, parent) =>
   t.isAssignmentExpression(parent) && parent.left === node;
 
-const isPlatformOS = (node, scope, isWrappedModule) =>
-  t.isIdentifier(node.property, os) &&
-  isImportOrGlobal(node.object, scope, [platform], isWrappedModule);
-
-const isReactPlatformOS = (node, scope, isWrappedModule) =>
-  t.isIdentifier(node.property, os) &&
-  t.isMemberExpression(node.object) &&
-  t.isIdentifier(node.object.property, platform) &&
-  isImportOrGlobal(
-    node.object.object,
-    scope,
-    [React, ReactNative],
-    isWrappedModule,
-  );
-
 const isProcessEnvNodeEnv = (node, scope) =>
   t.isIdentifier(node.property, nodeEnv) &&
   t.isMemberExpression(node.object) &&
@@ -90,24 +42,6 @@ const isProcessEnvNodeEnv = (node, scope) =>
   t.isIdentifier(node.object.object, processId) &&
   isGlobal(scope.getBinding(processId.name));
 
-const isPlatformSelect = (node, scope, isWrappedModule) =>
-  t.isMemberExpression(node.callee) &&
-  t.isIdentifier(node.callee.object, platform) &&
-  t.isIdentifier(node.callee.property, select) &&
-  isImportOrGlobal(node.callee.object, scope, [platform], isWrappedModule);
-
-const isReactPlatformSelect = (node, scope, isWrappedModule) =>
-  t.isMemberExpression(node.callee) &&
-  t.isIdentifier(node.callee.property, select) &&
-  t.isMemberExpression(node.callee.object) &&
-  t.isIdentifier(node.callee.object.property, platform) &&
-  isImportOrGlobal(
-    node.callee.object.object,
-    scope,
-    [React, ReactNative],
-    isWrappedModule,
-  );
-
 const isDev = (node, parent, scope) =>
   t.isIdentifier(node, dev) &&
   isGlobalOrFlowDeclared(scope.getBinding(dev.name)) &&
@@ -132,8 +66,8 @@ const inlinePlugin = {
 
       if (!isLeftHandSideOfAssignmentExpression(node, path.parent)) {
         if (
-          isPlatformOS(node, scope, opts.isWrapped) ||
+          inlinePlatform.isPlatformOS(node, scope, opts.isWrapped) ||
-          isReactPlatformOS(node, scope, opts.isWrapped)
+          inlinePlatform.isReactPlatformOS(node, scope, opts.isWrapped)
         ) {
           path.replaceWith(t.stringLiteral(opts.platform));
         } else if (isProcessEnvNodeEnv(node, scope)) {
@@ -150,8 +84,8 @@ const inlinePlugin = {
       const opts = state.opts;
 
       if (
-        isPlatformSelect(node, scope, opts.isWrapped) ||
+        inlinePlatform.isPlatformSelect(node, scope, opts.isWrapped) ||
-        isReactPlatformSelect(node, scope, opts.isWrapped)
+        inlinePlatform.isReactPlatformSelect(node, scope, opts.isWrapped)
       ) {
         const fallback = () =>
           findProperty(arg, 'default', () => t.identifier('undefined'));
@@ -167,16 +101,6 @@ const inlinePlugin = {
 
 const plugin = () => inlinePlugin;
 
-function checkRequireArgs(args, dependencyId) {
-  const pattern = t.stringLiteral(dependencyId);
-  return (
-    t.isStringLiteral(args[0], pattern) ||
-    (t.isMemberExpression(args[0]) &&
-      t.isNumericLiteral(args[0].property) &&
-      t.isStringLiteral(args[1], pattern))
-  );
-}
-
 type AstResult = {
   ast: Ast,
   code: ?string,