signal-desktop/ts/services/globalMessageAudio.ts
2023-03-02 13:55:40 -07:00

112 lines
2.6 KiB
TypeScript

// Copyright 2022 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import { noop } from 'lodash';
/**
* Wrapper around a global HTMLAudioElement that can update the
* source and callbacks without requiring removeEventListener
*/
class GlobalMessageAudio {
#audio: HTMLAudioElement = new Audio();
#url: string | undefined;
// true immediately after play() is called, even if still loading
#playing = false;
#onLoadedMetadata = noop;
#onTimeUpdate = noop;
#onEnded = noop;
#onDurationChange = noop;
#onError = noop;
constructor() {
// callbacks must be wrapped by function (not attached directly)
// so changes to the callbacks are effected
this.#audio.addEventListener('loadedmetadata', () =>
this.#onLoadedMetadata()
);
this.#audio.addEventListener('timeupdate', () => this.#onTimeUpdate());
this.#audio.addEventListener('durationchange', () =>
this.#onDurationChange()
);
this.#audio.addEventListener('ended', () => this.#onEnded());
}
load({
url,
playbackRate,
onLoadedMetadata,
onTimeUpdate,
onDurationChange,
onEnded,
onError,
}: {
url: string;
playbackRate: number;
onLoadedMetadata: () => void;
onTimeUpdate: () => void;
onDurationChange: () => void;
onEnded: () => void;
onError: (error: unknown) => void;
}) {
this.#url = url;
// update callbacks
this.#onLoadedMetadata = onLoadedMetadata;
this.#onTimeUpdate = onTimeUpdate;
this.#onDurationChange = onDurationChange;
this.#onEnded = onEnded;
this.#onError = onError;
// changing src resets the playback rate
this.#audio.src = this.#url;
this.#audio.playbackRate = playbackRate;
}
play(): void {
this.#playing = true;
this.#audio.play().catch(error => {
this.#onError(error);
});
}
pause(): void {
this.#audio.pause();
this.#playing = false;
}
get playbackRate() {
return this.#audio.playbackRate;
}
set playbackRate(rate: number) {
this.#audio.playbackRate = rate;
}
get playing() {
return this.#playing;
}
get url() {
return this.#url;
}
get duration(): number | undefined {
// the underlying Audio element can return NaN if the audio hasn't loaded
// we filter out 0 or NaN as they are not useful values downstream
return Number.isNaN(this.#audio.duration) || this.#audio.duration === 0
? undefined
: this.#audio.duration;
}
get currentTime() {
return this.#audio.currentTime;
}
set currentTime(value: number) {
this.#audio.currentTime = value;
}
}
export const globalMessageAudio = new GlobalMessageAudio();