RxJS5 emit array items over time and repeat forever

Question

I want to emit array items over time (a one second interval between each emit) and when all items have been emitted, repeat over and over.

I know how to do this, but

Answer 1

Observable.interval(1000).map(i => MY_ARRAY[i % MY_ARRAY.length])

Answer 2

zip is the go-to operator here, but using Observable.from dumps all values on subscribe, and requires zip to keep a copy of the values. This isn't ideal for large arrays. The original IEnumerable<T> overload for zip is implemented as zipIterable.

const MY_ARRAY = ['one','two','three'];
Rx.Observable.interval(1000).zipIterable(MY_ARRAY, (_, v) => v).subscribe(v => console.log(v))

Answer 3

You can use the zip operator:

const interval$ = Rx.Observable.interval(1000);
const items$ = Rx.Observable.from([1,2,3]);

const itemsOverTime$ = interval$.zip(items$).repeat();


itemsOverTime$.subscribe(([time, val]) => {
  console.log(val);
  // 1
  // 2
  // 3
  // 1
  // 2
  // 3
});