What is the procedure for obtaining an Observable for an Event?

Question

What is the procedure for obtaining an Observable for an Event?

How can I obtain an Observable of an Event in Angular 2?

For instance, is it possible to subscribe to a click event but only trigger after two clicks? Can we create an Observable of MouseClick event objects?

If I want to filter by button or ctrlKey, or have an Observable of KeyboardEvent and filter by key \ keyCode, or any potential future scenarios?

I came across which mentioned the property valueChanges as Observable<string>.

In addition, on https://github.com/angular/angular/issues/5489, there was a method demonstrated as follows:

this.clickStream = new Subject();
...
<button (click)="clickStream.next($event)">Click Me</button>

Is using the Subject method shown above the correct approach? I am uncertain.

While I lack experience with Angular 2 and RxJS, I am interested in both and exploring them for potential use in upcoming projects.

Edit

Here's my Plunker showcasing a simple click use case http://plnkr.co/edit/u1A7ve2fAYigjwaZ0x1v?p=preview

javascript angularjs rxjs

Answer 1

Answer №1

When working with Observables, you can use the fromEvent operator provided in RxJS, but first, you will need a reference to the native element. To obtain this reference, you can utilize viewChild or contentChild to access an elementRef.

To bind to the click event of the element, you can create a stream like this:

var clickStream = Observable.fromEvent(btnRef.nativeElement, 'click');

If your goal is to only emit events after two consecutive clicks (or once for every 2 clicks), you can achieve this using the bufferWithCount operator:

var triggerFor2Clicks = clickStream.bufferWithCount(2);

This will produce an array of 2 events at a time, enabling you to handle actions accordingly:

triggerFor2Clicks.subscribe(() => my2ClicksHandler);

It's worth noting that the argument in the subscribe function is empty ('()'), indicating that you are interested in the count of events rather than the specific event data.

Answer 2

When working with Observables, you can use the fromEvent operator provided in RxJS, but first, you will need a reference to the native element. To obtain this reference, you can utilize viewChild or contentChild to access an elementRef.

To bind to the click event of the element, you can create a stream like this:

var clickStream = Observable.fromEvent(btnRef.nativeElement, 'click');

If your goal is to only emit events after two consecutive clicks (or once for every 2 clicks), you can achieve this using the bufferWithCount operator:

var triggerFor2Clicks = clickStream.bufferWithCount(2);

This will produce an array of 2 events at a time, enabling you to handle actions accordingly:

triggerFor2Clicks.subscribe(() => my2ClicksHandler);

It's worth noting that the argument in the subscribe function is empty ('()'), indicating that you are interested in the count of events rather than the specific event data.

What is the procedure for obtaining an Observable for an Event?

Answer №1

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