CODEWITHSUNDEEP
angularrxjs5
Whisher
Whisher

Reputation: 32766

Argument of type '{ count: number; }' is not assignable to parameter of type 'number

With this code

const start$ = Observable.fromEvent(this.getNativeElement(this.start),'click');
    const stop$ = Observable.fromEvent(this.getNativeElement(this.stop),'click');
    const interval$ = Observable.interval(1000);
    const data = {count:0};

    const intervalThatStops$ = interval$
    .takeUntil(stop$);

start$
    .switchMapTo(intervalThatStops$)
    .startWith(data)
    .scan((acc,curr) => {
      return {
        count: acc.count+1
      };
    })
    .subscribe((x)=> console.log(x.count));

I've got in the console

Argument of type '{ count: number; }' is not assignable to parameter of type 'number | IScheduler'. Type '{ count: number; }' is not assignable to type 'IScheduler'. Property 'now' is missing in type '{ count: number; }'.)

a quick fix should be

.startWith<any>(data)

but what's the right way, please ?

Thanks in advance

Upvotes: 0

Views: 442

Answers (1)

snorkpete
snorkpete

Reputation: 14574

Taking it in parts,

start$
    .switchMapTo(intervalThatStops$)
    .startWith(data)

After that switchMapTo, your resulting Observable will emit values from the intervalThatStops$. And intervalThatStops$ is emitting pure numbers. So, when you try to .startWith({count:0}), you get the Typescript error because your observable is emitting numbers, but you're trying to startWith an object ({count: 0}).

The solution is to map your intervalThatStops$ to your object BEFORE using the startWith.

You can do this numerous ways - one possibility is:

start$
    .switchMapTo(intervalThatStops$)
    .map(i => ({count: i})))
    .startWith(data)

Upvotes: 2

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