README

angular-audio-context

An Angular wrapper for the Web Audio API's AudioContext.

Besides being a wrapper this module also patches the deprecated and prefixed versions of the AudioContext which are out there. It uses the standardized-audio-context to do so.

Usage

This module can be installed via npm like this:

npm install angular-audio-context

It provides an Angular Module that can be imported into your Angular app as usual.

import { AudioContextModule } from 'angular-audio-context';

@NgModule({
    imports: [AudioContextModule.forRoot('balanced')]
})
export class AppModule {}

The AudioContext can then be injected into your components and services.

import { Injectable } from '@angular/core';
import { AudioContext } from 'angular-audio-context';

@Injectable()
export class AnyService {
    constructor(private _audioContext: AudioContext) {}
}

In addition to the AudioContext, this module also provides a function called isSupported which returns a promise which either resolves to true or false depending on the currently used browser's Web Audio API support. An example usage might look like this:

import { Component, Inject } from '@angular/core';
import { isSupported } from 'angular-audio-context';

@Component({
    selector: 'any-component',
    template: '<span *ngIf="this.isSupported() | async">Yeah, your browser is supported.</span>'
})
export class AnyComponent {
    constructor(@Inject(isSupported) public isSupported) {}
}

In case you are missing a feature or found a bug just fork this repository or raise an issue. Thanks.

Example

The following component defintion shows how to implement a basic component which produces a beep each time the button inside the template gets clicked.

import { Component } from '@angular/core';
import { AudioContext } from 'angular-audio-context';

@Component({
    selector: 'my-beep',
    template: '<button (click)="beep()">beep</button>'
})
export class BeepComponent {
    constructor(private _audioContext: AudioContext) {}

    public async beep(): void {
        if (this._audioContext.state === 'suspended') {
            await this._audioContext.resume();
        }

        const oscillatorNode = this._audioContext.createOscillator();

        oscillatorNode.onended = () => oscillatorNode.disconnect();
        oscillatorNode.connect(this._audioContext.destination);

        oscillatorNode.start();
        oscillatorNode.stop(this._audioContext.currentTime + 0.5);
    }
}

Compatibility

Up to version 5 this module was compatible with Angular 1.

Alternatives

There is also module called ngWebAudio which tries to simplify the buffering and playback of a single audio file by utilizing the Web Audio API.

Acknowledgement

The naming of this module tries to align with the recommendations given in the Specification for reusable AngularJS components.

Usage no npm install needed!