add a audio module

Author: coocssweb

src/app/modules/audio.ts

@@ -0,0 +1,72 @@
+import { EMPTY_FUNCTION } from '../../constant';
+interface Options {
+    src: string,
+    autoPlay: boolean,
+    loop: boolean,
+    onPlay: Function,
+    onPause: Function,
+    onEnded: Function
+};
+
+export default class Audio {
+    static readonly defaultOptions: Options = {
+        src: '',
+        autoPlay: false,
+        loop: false,
+        onPlay: EMPTY_FUNCTION,
+        onPause: EMPTY_FUNCTION,
+        onEnded: EMPTY_FUNCTION
+    }
+
+    public isPlaying: boolean = false;
+    private element: HTMLAudioElement;
+
+    constructor (options: Options) {
+        options = { ...options, ...Audio.defaultOptions };
+        this.element = this.createAudioElement(options);
+    }
+
+    private createAudioElement (options: Options): HTMLAudioElement {
+        const wrapEvent = (userEvent = EMPTY_FUNCTION, proxyEvent = EMPTY_FUNCTION) => {
+            return (event: Event) => {
+                try {
+                    proxyEvent(event);
+                }
+                finally 
+                {
+                    userEvent(event);
+                }
+            };
+        };
+
+        const onPlay = () => {
+            this.isPlaying = true;
+        };
+        const onPause = () => {
+            this.isPlaying = false;
+        };
+        const onEnded = () => {
+            this.isPlaying = !options.loop;
+        }
+
+        let element = document.createElement('audio');
+        element.autoplay = options.autoPlay;
+        element.setAttribute('src', options.src);
+        element.setAttribute('loop', options.loop ? 'loop' : '');
+
+        // events for audio
+        element.onplay = wrapEvent(options.onPlay, onPlay);
+        element.onpause = wrapEvent(options.onPause, onPause);
+        element.onended = wrapEvent(options.onEnded, onEnded);
+
+        return element;
+    }
+    
+    public play () {
+        this.element.play();
+    }
+
+    public pause () {
+        this.element.pause();
+    }
+}