get the body of a block?

[jashmenn]

Say we had the following TypeScript:

  describe('initialization', () => {
    it('retrieves the artist', fakeAsync(
      inject([Router, SpotifyService, TestComponentBuilder],
             (router: Router,
              mockSpotifyService: MockSpotifyService,
              tcb: TestComponentBuilder) => {
        const fixture = tcb.createFakeAsync(RootCmp);
        advance(fixture);

        router.navigateByUrl('/artists/2');
        advance(fixture);

        expect(mockSpotifyService.getArtistSpy).toHaveBeenCalledWith('2');
      })));
  });

It would be nice to be able to easily select the interior arrow function.

A few things that might make this easy to do:

1. A way to select the body (Block) of an element
2. A way to select the individual arguments of a call
3. Seems easy and general enough to make a body operation.
4. Feels a bit tricky. We could do something like get(selection, n), which would give the nth element of selection. But it would be nice if it was generous in it's interpretation of the "listness" of the selection. E.g. if it's an array, the nth element but if it's a function it's the nth parameter. I'm not sure about this.

While we're at it, it would be nice to support getting the value of an object this way as well. E.g. if n was a string, and selection was an object, then you get the value of key n.

[fcoury]

Here's another case that seems related. I expected this snippet:

{lang=javascript,crop-query=.cliSystemConfigPackages-.barrels.forEach}
<<[code/first_app/angular2_reddit_base/src/system-config.ts](code/first_app/angular2_reddit_base/src/system-config.ts)

When executed against this code:

const cliSystemConfigPackages: any = {};
barrels.forEach((barrelName: string) => {
  cliSystemConfigPackages[barrelName] = { main: 'index' };
});

Gives this output:

When this is the output I expected to get: