pxloader/PxLoaderSound.js

PxLoader is a simple JavaScript library for creating preloaders and resource downloaders for HTML5 apps

/* global soundManager: true */
// PxLoader plugin to load sound using SoundManager2
(function(root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(['pxloader'], function(PxLoader) {
            return (root.PxLoaderSound = factory(PxLoader));
        });
    } else if (typeof module === 'object' && module.exports) {
        // Node. Does not work with strict CommonJS, but
        // only CommonJS-like environments that support module.exports,
        // like Node.
        module.exports = factory(require('pxloader'));
    } else {
        // Browser globals
        root.PxLoaderSound = factory(root.PxLoader);
    }
}(this, function(PxLoader) {
    function PxLoaderSound(id, url, tags, priority, options) {
        var self = this,
            loader = null;
    
        // For iOS and Android, soundManager2 uses a global audio object so we 
        // can't preload multiple sounds. We'll have to hope they load quickly
        // when we need to play them. Unfortunately, SM2 doesn't expose
        // a property to indicate its using a global object. For now we'll
        // use the same tests they use.
        var isIOS = navigator.userAgent.match(/(ipad|iphone|ipod)/i),
            isAndroid = navigator.userAgent.match(/android/i);
        this.useGlobalHTML5Audio = isIOS || isAndroid;
    
        this.tags = tags;
        this.priority = priority;
        this.sound = soundManager['createSound']({
            'id': id,
            'url': url,
            'autoLoad': false,
            'onload': function() {
                loader.onLoad(self);
            },
    
            // HTML5-only event: Fires when a browser has chosen to stop downloading.
            // "The user agent is intentionally not currently fetching media data,
            // but does not have the entire media resource downloaded."
            'onsuspend': function() {
                loader.onTimeout(self);
            },
    
            // Fires at a regular interval when a sound is loading and new data
            // has been received.
            'whileloading': function() {
                var bytesLoaded = this['bytesLoaded'],
                    bytesTotal = this['bytesTotal'];
    
                // TODO: provide percentage complete updates to loader?
                // see if we have loaded the file
                if (bytesLoaded > 0 && (bytesLoaded === bytesTotal)) {
                    loader.onLoad(self);
                }
            }
        });
    
        this.start = function(pxLoader) {
            // we need the loader ref so we can notify upon completion
            loader = pxLoader;
    
            // can't preload when a single global audio element is used
            if (this.useGlobalHTML5Audio) {
                loader.onTimeout(self);
            } else {
                this.sound['load']();
            }
        };
    
        this.checkStatus = function() {
            switch(self.sound['readyState']) {
                case 0:
                    // uninitialised
                    break;
                case 1:
                    // loading
                    break;
                case 2:
                    // failed/error
                    loader.onError(self);
                    break;
                case 3:
                    // loaded/success
                    loader.onLoad(self);
                    break;
            }
        };
    
        this.onTimeout = function() {
            loader.onTimeout(self);
        };
    
        this.getName = function() {
            return url;
        };
    }
    
    // add a convenience method to PxLoader for adding a sound
    PxLoader.prototype.addSound = function(id, url, tags, priority, options) {
        var soundLoader = new PxLoaderSound(id, url, tags, priority, options);
        this.add(soundLoader);
        return soundLoader.sound;
    };

    return PxLoaderSound;
}));