metro/transformer.js

/**
 * Copyright (c) 2015-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.
 *
 * Note: This is a fork of the fb-specific transform.js
 */
'use strict';

const babel = require('babel-core');
const inlineRequires = require('fbjs-scripts/babel/inline-requires');

function transform(src, filename, options) {
  const plugins = [];

  if (process.env.NODE_ENV === 'production') {
    plugins.push('node-env-inline', 'dunderscore-dev-inline');
  } else if (process.env.NODE_ENV === 'test') {
    plugins.push({
      position: 'after',
      transformer: inlineRequires,
    });
  }

  const result = babel.transform(src, {
    retainLines: true,
    compact: true,
    comments: false,
    filename,
    whitelist: [
      // Keep in sync with packager/react-packager/.babelrc
      'es6.arrowFunctions',
      'es6.blockScoping',
      'es6.classes',
      'es6.destructuring',
      'es6.parameters',
      'es6.properties.computed',
      'es6.properties.shorthand',
      'es6.spread',
      'es6.templateLiterals',
      'es7.asyncFunctions',
      'es7.trailingFunctionCommas',
      'es7.objectRestSpread',
      'flow',
      'react',
      'react.displayName',
      'regenerator',
    ],
    plugins,
    sourceFileName: filename,
    sourceMaps: false,
    extra: options || {},
  });

  return {
    code: result.code
  };
}

module.exports = function(data, callback) {
  let result;
  try {
    result = transform(data.sourceCode, data.filename);
  } catch (e) {
    callback(e);
    return;
  }

  callback(null, result);
};

// export for use in jest
module.exports.transform = transform;