RxJS5 emit array items over time and repeat forever

问题

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 I want to know if there is something more succinct than ..

const MY_ARRAY = ['one','two','three'];
const item$ = Rx.Observable.interval(1000).take(MY_ARRAY.length).repeat().map(x => MY_ARRAY[x]);
item$.subscribe(x => console.log(x));

thanks

output is ..

"one"

"two"

"three"

"one"

"two"

"three"

etc

EDIT:

ATOW, the answers here are summarised as ..

const ARR = ['one', 'two', 'three'];

// TAKE YOUR PICK THEY ALL DO THE SAME
const item$ = Rx.Observable.interval(1000).map(i => ARR[i % ARR.length]);
// const item$ = Rx.Observable.interval(1000).zip(ARR, (a, x) => x).repeat();
// const item$ = Rx.Observable.interval(1000).zip(ARR).repeat().map(x => x[1]);
// const item$ = Rx.Observable.interval(1000).take(ARR.length).repeat().map(i => ARR[i]);

item$.subscribe((x) => {
  console.log(x);
});

回答1:

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

回答2:

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
});

回答3:

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))

来源：https://stackoverflow.com/questions/41225446/rxjs5-emit-array-items-over-time-and-repeat-forever

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rxjs

rxjs5