Handling Multiple Streams with Merge

Share this video with your friends

Send Tweet

You often need to handle multiple user interactions set to different streams. This lesson shows hows Observable.merge behaves like a "logical OR" to have your stream handle one interaction OR another.

Vasyl
Vasyl
~ 7 years ago

Hi, I`m trying to start the same code in *.ts file, but receive an error: Error:(43, 18) TS2345:Argument of type '{ count: number; }' is not assignable to parameter of type '((acc: any) => { count: any; }) | ((acc: any) => { count: number; }) | IScheduler'. Type '{ count: number; }' is not assignable to type 'IScheduler'. Property 'now' is missing in type '{ count: number; }'. It is in the string with data param:

startButtonClick$ .switchMapTo(incOrReset$) .startWith(data) .scan((acc, curr) => curr(acc)) .subscribe((x)=> console.log(x)); However, this code works in *.js file. Can somebody help me with, how to solve current issue?

ganqqwerty
ganqqwerty
~ 7 years ago

mind-blowing, it really requires a new way of thinking, damn. I'm not sure I understand the diff between mapTo and switchMapTo. Is it correct that mapTo maps the stream to a function whereas switchMapTo maps the stream to another stream?

Bogdan
Bogdan
~ 6 years ago

Hi, I`m trying to start the same code in *.ts file, but receive an error: Error:(43, 18) TS2345:Argument of type '{ count: number; }' is not assignable to parameter of type '((acc: any) => { count: any; }) | ((acc: any) => { count: number; }) | IScheduler'. Type '{ count: number; }' is not assignable to type 'IScheduler'. Property 'now' is missing in type '{ count: number; }'. It is in the string with data param:

startButtonClick$ .switchMapTo(incOrReset$) .startWith(data) .scan((acc, curr) => curr(acc)) .subscribe((x)=> console.log(x)); However, this code works in *.js file. Can somebody help me with, how to solve current issue?

Hello! Not sure best or not, but i find way to resolve this (I have RxJS version 6.3.3). startStream.pipe( switchMapTo(merge( _interval.pipe(mapTo(inc)), resetStream.pipe(mapTo(data)) )), startWith(data), scan((acc: number, curr:(acc:number)=>number) => curr(acc)) ).subscribe((arg) => { console.log(arg) });

Bogdan
Bogdan
~ 6 years ago

UDP: Tips above correct if you use data as number, if data is object, as in lesson above, correct be:

startStream.pipe(
    switchMapTo(merge(
        _interval.pipe(mapTo(inc)),
        resetStream.pipe(mapTo(() => 0))
    )),
    startWith(0),
    scan((acc: {count: number}, curr:(acc:{count: number})=>{count: number}) => curr(acc))
).subscribe((arg) => {
    console.log(arg)
});