如何在零时间内获得RxJS Observable事件？

Question

I'm collecting all the events of an Observable to a data array:

 const obs$ = Rx.Observable .interval(500) .take(4); let data = []; const start = performance.now(); obs$.subscribe( value => { data.push({ time: performance.now() - start, data: value }); }, () => {}, () => { console.log(JSON.stringify(data, null, 2)); } ); 

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Is it possible to "foresee the future" and get the same data array without waiting 2 seconds ?

To clarify, I'm trying to find a way to wrap somehow a given Observable ( obs$ in the example above) with a custom timer/scheduler so I could get the events immediately.

Answer 1

You can create an instance of the VirtualTimeScheduler and can specify it in the call to interval .

If you then call flush on the scheduler after subscribing, the events will be emitted immediately:

 const scheduler = new Rx.VirtualTimeScheduler(); const obs$ = Rx.Observable .interval(500, scheduler) .take(4); let data = []; const start = scheduler.now(); obs$.subscribe( value => { data.push({ time: scheduler.now() - start, data: value }); }, () => {}, () => { console.log(JSON.stringify(data, null, 2)); } ); scheduler.flush(); 

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