Fix Edge support - mp3 only for now

src/js/HuesEditor.js

@@ -1225,14 +1225,14 @@ HuesEditor.prototype.drawWave = function() {
     
     this.waveContext.clearRect(0, 0, width, WAVE_HEIGHT_PIXELS);
     
-    if(this.buildWave && minTime < 0) {
-        let bLen = this.core.soundManager.buildLength;
+    let bLen = this.core.soundManager.buildLength;
+    if(this.buildWave && bLen && minTime < 0) {
         let center = Math.floor((now + bLen) / bLen * this.buildWave.width);
         this.drawOneWave(this.buildWave, center, width);
     }
     
-    if(this.loopWave && maxTime > 0) {
-        let loopLen = this.core.soundManager.loopLength;
+    let loopLen = this.core.soundManager.loopLength;
+    if(this.loopWave && loopLen && maxTime > 0) {
         let clampedNow = (minTime % loopLen) + span;
         let center = Math.floor(clampedNow / loopLen * this.loopWave.width);
         this.drawOneWave(this.loopWave, center, width);
@@ -1253,14 +1253,6 @@ HuesEditor.prototype.drawWave = function() {
     this.waveContext.stroke();
 };
 
-HuesEditor.prototype.alert = function(msg) {
-    this.statusMsg.classList.remove("fade");
-    this.statusMsg.textContent = msg;
-    // Trigger a reflow and thus restart the animation
-    var useless = this.statusMsg.offsetWidth;
-    this.statusMsg.classList.add("fade");
-};
-
 HuesEditor.prototype.drawOneWave = function(wave, center, width) {
     this.waveContext.drawImage(wave,
                                center - width/2, 0,        // source x/y
@@ -1269,6 +1261,14 @@ HuesEditor.prototype.drawOneWave = function(wave, center, width) {
                                width, WAVE_HEIGHT_PIXELS); // dest width/height
 };
 
+HuesEditor.prototype.alert = function(msg) {
+    this.statusMsg.classList.remove("fade");
+    this.statusMsg.textContent = msg;
+    // Trigger a reflow and thus restart the animation
+    var useless = this.statusMsg.offsetWidth;
+    this.statusMsg.classList.add("fade");
+};
+
 HuesEditor.prototype.generateXML = function() {
     if(!this.song) {
         return null;

src/js/SoundManager.js

@@ -67,10 +67,11 @@ SoundManager.prototype.init = function() {
             try {
                 // More info at http://caniuse.com/#feat=audio-api
                 window.AudioContext = window.AudioContext || window.webkitAudioContext;
-                this.context = new window.AudioContext();
                 // These don't always exist
-                this.context.suspend = this.context.suspend || Promise.resolve;
-                this.context.resume = this.context.resume || Promise.resolve;
+                AudioContext.prototype.suspend = AudioContext.prototype.suspend || (() => {return Promise.resolve();});
+                AudioContext.prototype.resume = AudioContext.prototype.resume || (() => {return Promise.resolve();});
+                
+                this.context = new window.AudioContext();
                 this.gainNode = this.context.createGain();
                 this.gainNode.connect(this.context.destination);
             } catch(e) {