[angular] How can I create an observable with a delay

Question

For testing purposes, I'm creating Observable objects that replace the observable that would be returned by an actual http call with Http.

My observable is created with the following code:

fakeObservable = Observable.create(obs => {
  obs.next([1, 2, 3]);
  obs.complete();
});

The thing is, this observable emits immediatly. Is there a way to add a custom delay to its emission?

Track

I tried this:

fakeObservable = Observable.create(obs => {
  setTimeout(() => {
    obs.next([1, 2, 3]);
    obs.complete();
  }, 100);
});

But it doesn't seem to work.

import * as Rx from 'rxjs/Rx';

We should add the above import to make the blow code to work

Let obs = Rx.Observable
    .interval(1000).take(3);

obs.subscribe(value => console.log('Subscriber: ' + value));

It's little late to answer ... but just in case may be someone return to this question looking for an answer

'delay' is property(function) of an Observable

fakeObservable = Observable.create(obs => {
  obs.next([1, 2, 3]);
  obs.complete();
}).delay(3000);

This worked for me ...

In RxJS 5+ you can do it like this

import { Observable } from "rxjs/Observable";
import { of } from "rxjs/observable/of";
import { delay } from "rxjs/operators";

fakeObservable = of('dummy').pipe(delay(5000));

In RxJS 6+

import { of } from "rxjs";
import { delay } from "rxjs/operators";

fakeObservable = of('dummy').pipe(delay(5000));

If you want to delay each emitted value try

from([1, 2, 3]).pipe(concatMap(item => of(item).pipe(delay(1000))));

What you want is a timer:

// RxJS v6+
import { timer } from 'rxjs';

//emit [1, 2, 3] after 1 second.
const source = timer(1000).map(([1, 2, 3]);
//output: [1, 2, 3]
const subscribe = source.subscribe(val => console.log(val));