codehs-graphics/audioContext.js

Helpers used to run graphics problems in the CodeHS editor.

'use strict';
/*
 * Defines a cross-browser compatible way of creating a new AudioContext.
 * Returns 0 and logs an error message if creating a new AudioContext is not possible.
 */

function getAudioContext() {
    // Test for browser compatibility
    // Source: https://www.safaribooksonline.com/library/view/web-audio-api/9781449332679/s01_2.html
    var contextClass =
        window.AudioContext ||
        window.webkitAudioContext ||
        window.mozAudioContext ||
        window.oAudioContext ||
        window.msAudioContext;
    if (contextClass) {
        // Web Audio API is available. Attempt to construct an AudioContext
        try {
            return new contextClass();
        } catch (e) {
            console.log(
                'Too many AudioContexts are in use. Please close all browser windows and retry.'
            );
            return 0;
        }
    } else {
        // Web Audio API is not available
        console.log(
            'Web Audio is not supported in this browser. Please use the most up to date version of Chrome, Firefox, or Safari.'
        );
        return 0;
    }
}

module.exports = getAudioContext;