Tone.js/Tone/core/Global.ts
2019-06-19 10:25:05 -04:00

62 lines
1.6 KiB
TypeScript

import { version } from "../version";
/**
* The global audio context which is getable and assignable through
* getContext and setContext
*/
let globalContext: BaseAudioContext;
// @ts-ignore
globalContext = window.TONE_AUDIO_CONTEXT;
/**
* Returns the default system-wide AudioContext
*/
export function getContext(): BaseAudioContext {
if (!globalContext) {
globalContext = new AudioContext();
// @ts-ignore
window.TONE_AUDIO_CONTEXT = globalContext;
}
return globalContext;
}
/**
* Set the default audio context
*/
export function setContext(context: BaseAudioContext): void {
globalContext = context;
// @ts-ignore
window.TONE_AUDIO_CONTEXT = globalContext;
}
/**
* Most browsers will not play _any_ audio until a user
* clicks something (like a play button). Invoke this method
* on a click or keypress event handler to start the audio context.
* More about the Autoplay policy
* [here](https://developers.google.com/web/updates/2017/09/autoplay-policy-changes#webaudio)
* @example
* document.querySelector('#playbutton').addEventListener('click', () => Tone.start())
*/
export function start(): Promise <void> {
if (globalContext instanceof AudioContext) {
return globalContext.resume();
} else {
return Promise.resolve();
}
}
/**
* Log Tone.js + version in the console.
*/
if (!this.TONE_SILENCE_LOGGING) {
let prefix = "v";
// @ts-ignore
if (version === "dev") {
prefix = "";
}
const printString = ` * Tone.js ${prefix}${version} * `;
// tslint:disable-next-line: no-console
console.log(`%c${printString}`, "background: #000; color: #fff");
}