transformer for node modules

rn-cli.config.js

module.exports = {

  /**
   * Add search paths to the packager. Equivalent to the
   * `--projectRoots` command line argument.
   *
   * Your app project directory is the default, but you can easily add
   * additional directories.
   *
   * This is very handy when you maintain all your software in one big
   * repo, which means your app's dependencies aren't necessarily just
   * located in `./node_modules` but potentially in sibling
   * directories or other locations.
   */
  getProjectRoots() {
    return [__dirname];
  },

  /**
   * Specify additional file extensions for assets. For example, if
   * you want to include a .ttf file, you would return ['ttf'] from
   * here and use `require('./fonts/example.ttf')` inside your app.
   *
   * Equivalent to the `--assetExts` command line argument.
   */
  getAssetExts() {
    return [];
  },

  /**
   * Specify any additional platforms to be used by the packager.
   * For example, if you want to add a "custom" platform, and use modules
   * ending in .custom.js, you would return ['custom'] here.
   *
   * Equivalent to the `--platforms` command line argument.
   */
  getPlatforms() {
    return [];
  },

  /**
   * The React Native packager can be a bit fussy. For instance, it
   * does not like come across duplicate packages. It can also be slow
   * to traverse deep directory structures that you know won't have
   * app dependencies in them. Putting those directories on the
   * blacklist will stop the packager from traversing into them.
   */
  getBlacklistRE() {
    const blacklist = require('metro/src/blacklist');
    const additionalBlacklist = [
      /ignore-this-directory\/.*/,
    ];
    return blacklist(additionalBlacklist);
  },

  /**
   * This is the bombshell. New in React Native 0.30, this allows you
   * to specify your own code transformer.
   *
   * In essense, instead of specifying your own `.babelrc` file,
   * you'll want to specify your own transformer. That way, when
   * running a regular node program such as the packager itself, the
   * special transforms your app needs won't be applied.
   *
   * Equivalent to the `--transformer` command line argument.
   */
  getTransformModulePath() {
    return require.resolve('./transformer');
  },
};

transformer.js

const babel = require('babel-core');

/**
 * This is your `.babelrc` equivalent.
 */
const babelRC = {
  presets: [require('babel-preset-react-native')],
  plugins: [
    // The following plugin will rewrite imports. Reimplementations of node
    // libraries such as `assert`, `buffer`, etc. will be picked up
    // automatically by the React Native packager.  All other built-in node
    // libraries get rewritten to their browserify counterpart.
    [require('babel-plugin-rewrite-require'), {
      aliases: {
        constants: 'constants-browserify',
        crypto: 'react-native-crypto',
        dns: 'node-libs-browser/mock/dns',
        domain: 'domain-browser',
        fs: 'node-libs-browser/mock/empty',
        http: 'stream-http',
        https: 'https-browserify',
        net: 'node-libs-browser/mock/net',
        os: 'os-browserify/browser',
        path: 'path-browserify',
        querystring: 'querystring-es3',
        stream: 'stream-browserify',
        _stream_duplex: 'readable-stream/duplex',
        _stream_passthrough: 'readable-stream/passthrough',
        _stream_readable: 'readable-stream/readable',
        _stream_transform: 'readable-stream/transform',
        _stream_writable: 'readable-stream/writable',
        sys: 'util',
        timers: 'timers-browserify',
        tls: 'node-libs-browser/mock/tls',
        tty: 'tty-browserify',
        vm: 'vm-browserify',
        zlib: 'browserify-zlib',
        randombytes: 'react-native-randombytes',
        bip39: 'react-native-bip39',
        // tweetnacl: 'tweetnacl-rn',
        // You can add your own, much like webpack aliases:
        'corporate-lib': 'corporate-lib-react-native',

        // You can also mock any libraries that you don't need to support on
        // React Native, but have to be present for 3rd party code to work:
        'some-third-party-dependency': 'node-libs-browser/mock/empty',
      },
      throwForNonStringLiteral: true,
    }],
  ],
};

function transform({src, filename, options}) {
  const babelConfig = Object.assign({}, babelRC, {
    filename,
    sourceFileName: filename,
  });
  console.log('S================')
  console.log(filename)
  console.log('E================')
  const result = babel.transform(src, babelConfig);
  return {
    ast: result.ast,
    code: result.code,
    map: result.map,
    filename: filename,
  };
}
module.exports.transform = transform;

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

• Put rn-cli.config.js and transformer.js in the root folder
• Install all modules that used in transformer.js using npm install <module-name> --save