How to use the core-js/library/fn/map function in core-js

getInitialState: function () {
    this._renderedSceneMap = new Map();

    let routeStack = this.props.initialRouteStack || [this.props.initialRoute];
    invariant(
      routeStack.length >= 1,
      'Navigator requires props.initialRoute or props.initialRouteStack.'
    );
    let initialRouteIndex = routeStack.length - 1;
    if (this.props.initialRoute) {
      initialRouteIndex = routeStack.indexOf(this.props.initialRoute);
      invariant(
        initialRouteIndex !== -1,
        'initialRoute is not in initialRouteStack.'
      );
    }
    return {
      sceneConfigStack: routeStack.map(

render: function() {
    let newRenderedSceneMap = new Map();
    let scenes = this.state.routeStack.map((route, index) => {
      let renderedScene;
      if (this._renderedSceneMap.has(route) &&
          index !== this.state.presentedIndex) {
        renderedScene = this._renderedSceneMap.get(route);
      } else {
        renderedScene = this._renderScene(route, index);
      }
      newRenderedSceneMap.set(route, renderedScene);
      return renderedScene;
    });
    this._renderedSceneMap = newRenderedSceneMap;
    return (

render: function () {
    let newRenderedSceneMap = new Map();
    let scenes = this.state.routeStack.map((route, index) => {
      let renderedScene;
      if (this._renderedSceneMap.has(route) &&
        index !== this.state.presentedIndex) {
        renderedScene = this._renderedSceneMap.get(route);
      } else {
        renderedScene = this._renderScene(route, index);
      }
      newRenderedSceneMap.set(route, renderedScene);
      return renderedScene;
    });
    this._renderedSceneMap = newRenderedSceneMap;
    return (

getInitialState: function() {
    this._renderedSceneMap = new Map();

    let routeStack = this.props.initialRouteStack || [this.props.initialRoute];
    invariant(
      routeStack.length >= 1,
      'Navigator requires props.initialRoute or props.initialRouteStack.'
    );
    let initialRouteIndex = routeStack.length - 1;
    if (this.props.initialRoute) {
      initialRouteIndex = routeStack.indexOf(this.props.initialRoute);
      invariant(
        initialRouteIndex !== -1,
        'initialRoute is not in initialRouteStack.'
      );
    }
    return {
      sceneConfigStack: routeStack.map(