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Angular 2 official example: strongly typed error displaying json object array

I cannot figure out how to map the json object array returned from the web service to a properly typed object array in an Angular 2 application.

As you can see in the official Angular 2 example in plunker, the expected objects are not of type Hero, they are of type Object and hero: Hero [], the member of HeroListComponent is actually Object []. You can see in the console that the array is not strongly typed:

http://plnkr.co/edit/Qa22yzPh3JWI8lNZ99Ik?p=preview

I added an additional call to console.log () to add the hero command, you can see in the browser console that we do not have Hero [], but Object [].

Thus, it is obvious that the conversion does not work:

    this.http.get(this._heroesUrl)
            .map(res => <Hero[]> res.json().data)
            .catch(this.handleError);

and instead of Object [] we get Object [].

, json ?

: https://angular.io/docs/ts/latest/guide/server-communication.html

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Hero []: .map(res = > res.json(). data)

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