diff on groupBy and map in rxjs

diff on groupBy and map in rxjs.js

//
//groupBy: <K, R>(keySelector: (value: T) => K, elementSelector?: (value: T) => R, durationSelector?: (group: GroupedObservable<K, R>) => Observable<any>) => Observable<GroupedObservable<K, R>>;
//
//map: <R>(project: (x: T, ix?: number) => R, thisArg?: any) => Observable<R>;

var codes = [
  { keyCode: 38}, // up
  { keyCode: 38}, // up
  { keyCode: 40}, // down
  { keyCode: 40}, // down
  { keyCode: 37}, // left
  { keyCode: 39}, // right
  { keyCode: 37}, // left
  { keyCode: 39}, // right
  { keyCode: 66}, // b
  { keyCode: 38}, // up
  { keyCode: 38}, // up
  { keyCode: 65}  // a
];

//Observable.from(codes)
//  .map((x)=> x)
//  .subscribe(s => console.log(`next => ${s.keyCode}`))


Observable.from(codes).groupBy(
   (x) => { return x.keyCode; },
   (x) => { return x; }
).subscribe(
 (obs) => {
    // Print the count
    obs.subscribe( (x) => {
      console.log('Count: ' + JSON.stringify(x));
    });
  },
  (err) => {
    console.log('Error: ' + err);
  },
  () => {
    console.log('Completed');
  });