How to use Observables operators with EventEmitter (FormModel.valueChanges) in Angular2 [duplicate]

Question

I'm trying to use some simple operators on a EventEmitter (from a FormModel.valueChanges) but I don't know how it's suppose to be done.

The class EventEmitter extends from Subject
export declare class EventEmitter<T> extends Subject<T>
so I tried several things:

this.patientForm.valueChanges.debounceTime(400) this.patientForm.valueChanges.source.debounceTime(400) this.patientForm.valueChanges.asObservable().debounceTime(400) Observable.create(this.patientForm.valueChanges).debounceTime(400)

tried in the constructor and in ngOnInit
the source is always undefined and the operators don't exist in the class.

I have this import import {Observable} from 'rxjs'; could be something with that?

(what I'm trying to do is save the form state in a Redux store, but don't want to do it in every keystroke)

Looks like a dup of stackoverflow.com/questions/34515173/… — Günter Zöchbauer
– Günter Zöchbauer, Commented Apr 10, 2016 at 15:27

Thierry Templier · Accepted Answer · 2016-04-10 16:34:05Z

2

As Günter stated, operators aren't by default included

To import the Observable class, just use the following. In this case, you will have all the operators within the Observable class:

import {Observable} from 'rxjs/Rx';

To only have the debounceTime operator, you could use this:

import {Observable} from 'rxjs/Observable';
import 'rxjs/add/operator/debounceTime';

Then the right way to use the debounceTime operator is:

this.patientForm.valueChanges.debounceTime(400).subscribe((val) => {
  (...)
});

See this article for more details:

https://jaxenter.com/reactive-programming-http-and-angular-2-124560.html

answered Apr 10, 2016 at 16:34

Thierry Templier

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1 Comment

Sebastián Gaviria Over a year ago

import {Observable} from 'rxjs/Rx'; didn't work (I think the operators aren't added at that point), instead I used import 'rxjs/Rx';. Is that a bad idea?

Günter Zöchbauer · Accepted Answer · 2016-04-10 15:27:32Z

0

You need to import the operators

import 'rxjs/add/operator/debounceTime'

or all of them at once

import 'rxjs/Rx';

answered Apr 10, 2016 at 15:27

Günter Zöchbauer

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