Angular 16 and ViewChild and HTMLMediaElement

Angular 16 and ViewChild and HTMLMediaElement

While working on an angular application where I had to develop the ability to manually control a video stream. Simple controls like, play, pause, and volume. “No problem!” I thought. HTML5 has these controls built-in and it will be super-simple to manipulate those methods with JS.

This simple task took me on a 3-day journey into the 7th circle of hell. I couldn’t get basic controls to work, couldn’t get any video helper library functional, and nothing I was doing seemed to be doing what it was supposed to! ARGH!

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

@Component({
  selector: 'tvpreview',
  templateUrl: './tvpreview.component.html',
  styleUrls: ['./tvpreview.component.scss'],
})

export class TVPreviewComponent implements AfterViewInit {
  @ViewChild("tvpreview") tvpreview: ElementRef;

  streamLoaded = false;
  streamStarted = false;

  ngAfterViewInit() {
    this.tvpreview.nativeElement.onloadeddata = (event) => {
        console.log('Video data is loaded.');
        this.streamLoaded = true;
    };

    this.tvpreview.nativeElement.onplaying = (event) => {
        console.log('Video is no longer paused.');
        this.streamStarted = true;
    };
  }

  play() {
    this.tvpreview.nativeElement.play();
  }

  pause() {
    this.tvpreview.nativeElement.pause();
  }

  setMute() {
    this.tvpreview.nativeElement.muted =
      !this.tvpreview.nativeElement.muted;
  }
}

Looks pretty simple, right?

In the above example, I was able to get play() to work, and setMute() to work, but pause() would error out with (to summarize): nativeElement.pause is not a function. What? So play() and muted are there, but pause isn’t? What in the world is happening???

After 3 days of banging my head against this problem and/or trying to find ways around it, I finally figured it out. The problem was this line:

@ViewChild("tvpreview") tvpreview: ElementRef;

Do you see it??

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It’s the frickin’ QUOTES!!!!

I used this instead:

@ViewChild('tvpreview') tvpreview: ElementRef;

… and all is right with the world…

Hope this helps you not make the same mistake I did. =)

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