code: function dependency(deps, name) {
    if (name in deps && typeof deps[name] !== 'undefined') {
      return deps[name];
    }
    throw new Error('grunt-rewrite.registerTask requires dependency "' + name + '"');
  }
docs: Return the named dependency or throw an error that it is absent.
  @param  {Object} deps
  @param  {String} name
  @throws {Error}
  @return {Mixed}