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in Technique[技术] by (71.8m points)

rxjs - Angular 2 - subscribing to Observable.fromEvent error: "Invalid event target"

I am getting a weird error when trying to subscribe to an Observable.

Here is a watered down version of the code which presents the problem:

import {Component, Input, OnInit, ViewChild} from '@angular/core';
import Rx from 'rxjs/Rx';

@Component({
  selector: 'action-overview-description',
  template: require('./actionOverviewDescription.html')
})
export class ActionOverviewDescription  {
  @ViewChild('button') button;

  constructor() {}
  
   ngOnInit() {

    let buttonStream$ = Rx.Observable.fromEvent(this.button, 'click')
        .subscribe(res => console.log(res));

  }
}
<button #input>Button</button>
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by (71.8m points)

The problem is the lifecycle hook you're using. The element is not yet creating in DOM when ngOnInit is called. Instead, you should use ngAfterViewInit.

Could you try the following code:

import { Component, ViewChild, ElementRef, AfterViewInit } from '@angular/core';
import { Observable, fromEvent } from 'rxjs';

@Component({
  template: '<button #input>Button</button>'
})
export class ActionOverviewDescription implements AfterViewInit {
  @ViewChild('input') button: ElementRef;

  ngAfterViewInit() {
    let buttonStream$ = Observable.fromEvent(this.button.nativeElement, 'click')
        .subscribe(res => console.log(res));

  }
}

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