RxJS .zip and .switchLatest

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/4.1.0/rx.all.js"></script>

CSS

textarea {
    font-family:"Courier New", monospace;
    font-size: 12px;
    width: 100%;
    height: 120px;
}

JavaScript

var Observable = Rx.Observable;

Observable.of(['a', 1], ['a', 1], ['a', 0], ['a', 1])
  .distinctUntilChanged(x => x[1])
  .subscribe(x => console.log(x))

Observable.of({key: 'a', state: 1}, {key: 'a', state: 2}, {key: 'a', state: 0}, {key: 'a', state: 1})
  .distinctUntilChanged(x => x.state)
  .subscribe(x => console.log(x))

Observable.of({value: 42}, {value: 42}, {value: 24}, {value: 24})
  .distinctUntilChanged(x => x.value)
  .subscribe(
    function (x) {
      console.log('Next: ', x)
    },
    function (err) {
      console.log('Error: ' + err)
    },
    function () {
      console.log('Completed')
    }
  )