babel-preset-react-native: only require plugins once

Reviewed By: cpojer

Differential Revision: D6795591

fbshipit-source-id: 30b689e2cf72a4bf4bdae49113369ef536ed81d6

babel-preset/configs/main.js

@@ -5,86 +5,105 @@
  * 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.
- *
  */
 'use strict';
 
-var resolvePlugins = require('../lib/resolvePlugins');
+const resolvePlugins = require('../lib/resolvePlugins');
+const resolvePlugin = resolvePlugins.resolvePlugin;
+
+const defaultPlugins = resolvePlugins([
+  'syntax-class-properties',
+  'syntax-trailing-function-commas',
+  'transform-class-properties',
+  'transform-es2015-block-scoping',
+  'transform-es2015-computed-properties',
+  'transform-es2015-destructuring',
+  'transform-es2015-function-name',
+  'transform-es2015-literals',
+  'transform-es2015-parameters',
+  'transform-es2015-shorthand-properties',
+  'transform-flow-strip-types',
+  'transform-react-jsx',
+  'transform-regenerator',
+  [
+    'transform-es2015-modules-commonjs',
+    {strict: false, allowTopLevelThis: true},
+  ],
+]);
+
+const checkES2015Constants = resolvePlugin('check-es2015-constants');
+const es2015ArrowFunctions = resolvePlugin('transform-es2015-arrow-functions');
+const es2015Classes = resolvePlugin('transform-es2015-classes');
+const es2015ForOf = resolvePlugin(['transform-es2015-for-of', {loose: true}]);
+const es2015Spread = resolvePlugin('transform-es2015-spread');
+const es2015TemplateLiterals = resolvePlugin(
+  'transform-es2015-template-literals'
+);
+const asyncFunctions = resolvePlugin('syntax-async-functions');
+const exponentiationOperator = resolvePlugin(
+  'transform-exponentiation-operator'
+);
+const objectAssign = resolvePlugin('transform-object-assign');
+const objectRestSpread = resolvePlugin('transform-object-rest-spread');
+const reactDisplayName = resolvePlugin('transform-react-display-name');
+const reactJsxSource = resolvePlugin('transform-react-jsx-source');
+const symbolMember = [require('../transforms/transform-symbol-member')];
 
 const getPreset = (src, options) => {
-  const plugins = [];
   const isNull = src === null || src === undefined;
   const hasClass = isNull || src.indexOf('class') !== -1;
   const hasForOf =
     isNull || (src.indexOf('for') !== -1 && src.indexOf('of') !== -1);
 
-  plugins.push(
-    'syntax-class-properties',
-    'syntax-trailing-function-commas',
-    'transform-class-properties',
-    'transform-es2015-block-scoping',
-    'transform-es2015-computed-properties',
-    'transform-es2015-destructuring',
-    'transform-es2015-function-name',
-    'transform-es2015-literals',
-    'transform-es2015-parameters',
-    'transform-es2015-shorthand-properties',
-    'transform-flow-strip-types',
-    'transform-react-jsx',
-    'transform-regenerator',
-    [
-      'transform-es2015-modules-commonjs',
-      {strict: false, allowTopLevelThis: true},
-    ]
-  );
+  const extraPlugins = [];
 
   if (isNull || src.indexOf('async') !== -1 || src.indexOf('await') !== -1) {
-    plugins.push('syntax-async-functions');
+    extraPlugins.push(asyncFunctions);
   }
   if (hasClass) {
-    plugins.push('transform-es2015-classes');
+    extraPlugins.push(es2015Classes);
   }
   if (isNull || src.indexOf('=>') !== -1) {
-    plugins.push('transform-es2015-arrow-functions');
+    extraPlugins.push(es2015ArrowFunctions);
   }
   if (isNull || src.indexOf('const') !== -1) {
-    plugins.push('check-es2015-constants');
+    extraPlugins.push(checkES2015Constants);
   }
   if (isNull || hasClass || src.indexOf('...') !== -1) {
-    plugins.push('transform-es2015-spread');
-    plugins.push('transform-object-rest-spread');
+    extraPlugins.push(es2015Spread);
+    extraPlugins.push(objectRestSpread);
   }
   if (isNull || src.indexOf('`') !== -1) {
-    plugins.push('transform-es2015-template-literals');
+    extraPlugins.push(es2015TemplateLiterals);
   }
   if (isNull || src.indexOf('**') !== -1) {
-    plugins.push('transform-exponentiation-operator');
+    extraPlugins.push(exponentiationOperator);
   }
   if (isNull || src.indexOf('Object.assign') !== -1) {
-    plugins.push('transform-object-assign');
+    extraPlugins.push(objectAssign);
   }
   if (hasForOf) {
-    plugins.push(['transform-es2015-for-of', {loose: true}]);
+    extraPlugins.push(es2015ForOf);
   }
   if (hasForOf || src.indexOf('Symbol') !== -1) {
-    plugins.push(require('../transforms/transform-symbol-member'));
+    extraPlugins.push(symbolMember);
   }
   if (
     isNull ||
     src.indexOf('React.createClass') !== -1 ||
     src.indexOf('createReactClass') !== -1
   ) {
-    plugins.push('transform-react-display-name');
+    extraPlugins.push(reactDisplayName);
   }
 
   if (options && options.dev) {
-    plugins.push('transform-react-jsx-source');
+    extraPlugins.push(reactJsxSource);
   }
 
   return {
     comments: false,
     compact: true,
-    plugins: resolvePlugins(plugins),
+    plugins: defaultPlugins.concat(extraPlugins),
   };
 };
 

babel-preset/lib/resolvePlugins.js

@@ -15,18 +15,24 @@
  * installed in the react-native package.
  */
 function resolvePlugins(plugins) {
-  return plugins.map(function(plugin) {
-    // Normalise plugin to an array.
-    if (!Array.isArray(plugin)) {
-      plugin = [plugin];
-    }
-    // Only resolve the plugin if it's a string reference.
-    if (typeof plugin[0] === 'string') {
-      plugin[0] = require('babel-plugin-' + plugin[0]);
-      plugin[0] = plugin[0].__esModule ? plugin[0].default : plugin[0];
-    }
-    return plugin;
-  });
+  return plugins.map(resolvePlugin);
+}
+
+/**
+ * Manually resolve a single Babel plugin.
+ */
+function resolvePlugin(plugin) {
+  // Normalise plugin to an array.
+  if (!Array.isArray(plugin)) {
+    plugin = [plugin];
+  }
+  // Only resolve the plugin if it's a string reference.
+  if (typeof plugin[0] === 'string') {
+    plugin[0] = require('babel-plugin-' + plugin[0]);
+    plugin[0] = plugin[0].__esModule ? plugin[0].default : plugin[0];
+  }
+  return plugin;
 }
 
 module.exports = resolvePlugins;
+module.exports.resolvePlugin = resolvePlugin;