How to get a Waveform Music Player with Angular/Typescript

Question

My goal is to set up a simple music player in my angular 8 project, that displays the inserted music in static wave form, similar to soundclouds player:

According to my search, this can be done with either:

Peaks JS: https://medium.com/better-programming/peaks-js-interact-with-audio-waveforms-b7cb5bd3939a
Amplitude JS : https://521dimensions.com/open-source/amplitudejs/docs/configuration/
or Wavesurfer JS: https://wavesurfer-js.org/

Unfortunately, none of them has a decent documentation on how to import this properly to angular or typescript in general.

I tried it with Wavesurfer JS but failed.

component.ts :

 import { WaveSurfer } from 'wavesurfer.js';

    export class MusicComponent {

    public wavesurfer

      constructor() {

        this.wavesurfer = WaveSurfer.create({
          container: '#waveform',
          waveColor: 'violet',
          progressColor: 'purple'
        });

        this.wavesurfer.load('./assets/img/hollywood.wav');



      }

    }

html

 <div id="waveform"></div>

The questions are now:
1. Is there some other good practice on how to implement such a player with angular, that i didnt find.
2. Is there a way to make wavesurf work in Angular, or is my code wrong.

Answer 1

Yes, it's possible, I did it. Check the code below (.ts):

import {Component, OnInit, ViewChild, ElementRef, AfterViewInit, ChangeDetectorRef} from '@angular/core';
import WaveSurfer from 'wavesurfer.js';
import TimelinePlugin from 'wavesurfer.js/dist/plugin/wavesurfer.timeline.min.js';
import Regions from 'wavesurfer.js/dist/plugin/wavesurfer.regions.min.js';

@Component({
  selector: 'app-graph',
  templateUrl: './graph.component.html',
  styleUrls: ['./graph.component.css']
})

export class GraphComponent implements OnInit, AfterViewInit {

  wave: WaveSurfer = null;
  url = '../../assets/sinus.wav';
  public graph = undefined;


  constructor( private cdr: ChangeDetectorRef) {
  }


  ngOnInit(): void {


  }

  onPreviewPressed(): void {
    if (!this.wave) {
      this.generateWaveform();
    }

    this.cdr.detectChanges();

    Promise.resolve().then(() => this.wave.load(this.url));
  }

  onStopPressed(): void {
    this.wave.stop();
  }

  generateWaveform(): void {
    Promise.resolve(null).then(() => {
      this.wave = WaveSurfer.create({
        container: '#waveform',
        waveColor: 'violet',
        progressColor: 'purple',
        plugins: [
          TimelinePlugin.create({
            container: '#wave-timeline'
          }),
          Regions.create({
            regions: [
              {
                start: 1,
                end: 3,
                loop: false,
                color: 'hsla(400, 100%, 30%, 0.5)'
              }, {
                start: 5,
                end: 7,
                loop: false,
                color: 'hsla(200, 50%, 70%, 0.4)'
              }
            ],
            dragSelection: {
              slop: 5
            }
          })
        ]
      });

      this.wave.on('ready', () => {
        alert('I\'m ready');
        this.wave.play();
      });
    });
  }
}

And on the HTML file:

  <div id="waveform"></div>
  <div id="wave-timeline"></div>
  <div *ngIf="wave" class="controls">
    <button (click)="onStopPressed()">Stop</button>
  </div>
  <button (click)="onPreviewPressed()">Click me</button>