docs: function browserifyAnonymousLabeler(bundler) {
    var isValid = bundler && (typeof bundler === 'object') &&
      (typeof bundler.on === 'function') && (typeof bundler.pipeline === 'object');
    if (isValid) {
      bundler.pipeline
        .get('label')
        .push(anonymousLabeler());
    }
    else {
      throw new Error('Expected a browserify bundler instance');
    }
  }