Use Web audio API

src/SoundManager.ts

@@ -0,0 +1,61 @@
+/**
+ * Copyright (c) 2018 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { ITerminal, ISoundManager } from './Interfaces';
+
+// Source: https://freesound.org/people/altemark/sounds/45759/
+// This sound is released under the Creative Commons Attribution 3.0 Unported
+// (CC BY 3.0) license. It was created by 'altemark'. No modifications have been
+// made, apart from the conversion to base64.
+export const DefaultBellSound = 'data:audio/wav;base64,UklGRigBAABXQVZFZm10IBAAAAABAAEARKwAAIhYAQACABAAZGF0YQQBAADpAFgCwAMlBZoG/wdmCcoKRAypDQ8PbRDBEQQTOxRtFYcWlBePGIUZXhoiG88bcBz7HHIdzh0WHlMeZx51HmkeUx4WHs8dah0AHXwc3hs9G4saxRnyGBIYGBcQFv8U4RPAEoYRQBACD70NWwwHC6gJOwjWBloF7gOBAhABkf8b/qv8R/ve+Xf4Ife79W/0JfPZ8Z/wde9N7ijtE+wU6xvqM+lb6H7nw+YX5mrlxuQz5Mzje+Ma49fioeKD4nXiYeJy4pHitOL04j/jn+MN5IPkFOWs5U3mDefM55/ogOl36m7rdOyE7abuyu8D8Unyj/Pg9D/2qfcb+Yn6/vuK/Qj/lAAlAg==';
+
+export class SoundManager implements ISoundManager {
+
+    private _terminal: ITerminal;
+    private _audioContext: AudioContext;
+
+    constructor(_terminal: ITerminal) {
+        this._terminal = _terminal;
+    }
+
+    public playBellSound(): void {
+        if (!this._audioContext) {
+            this._audioContext = new (window.AudioContext || window.webkitAudioContext)();
+        }
+
+        if (this._audioContext) {
+            let bellAudioSource = this._audioContext.createBufferSource();
+            let context = this._audioContext;
+            this._audioContext.decodeAudioData(this.base64ToArrayBuffer(this.removeMimeType(this._terminal.options.bellSound)), function (buffer) {
+                bellAudioSource.buffer = buffer;
+                bellAudioSource.connect(context.destination);
+                bellAudioSource.start(0);
+            });
+        }
+        else {
+            console.warn('Sorry, but the Web Audio API is not supported by your browser. Please, consider upgrading to the latest version');
+        }
+    }
+
+    private base64ToArrayBuffer(base64: string): ArrayBuffer {
+        const binaryString = window.atob(base64);
+        const len = binaryString.length;
+        let bytes = new Uint8Array(len);
+
+        for (let i = 0; i < len; i++) {
+            bytes[i] = binaryString.charCodeAt(i);
+        }
+
+        return bytes.buffer;
+    }
+
+    private removeMimeType(dataURI: string): string {
+        // Split the input to get the mime-type and the data itself
+        const SplitURI = dataURI.split(',');
+
+        // Return only the data
+        return SplitURI[1];
+    }
+}