docs(webSocket): adds webSocket and WebSocketSubject documentation (#2223)

Author: feloy

src/observable/dom/WebSocketSubject.ts

@@ -42,7 +42,36 @@ export class WebSocketSubject<T> extends AnonymousSubject<T> {
   }
 
   /**
-   * @param urlConfigOrSource
+   * Wrapper around the w3c-compatible WebSocket object provided by the browser.
+   *
+   * @example <caption>Wraps browser WebSocket</caption>
+   *
+   * let subject = Observable.webSocket('ws://localhost:8081');
+   * subject.subscribe(
+   *    (msg) => console.log('message received: ' + msg),
+   *    (err) => console.log(err),
+   *    () => console.log('complete')
+   *  );
+   * subject.next(JSON.stringify({ op: 'hello' }));
+   *
+   * @example <caption>Wraps WebSocket from nodejs-websocket (using node.js)</caption>
+   *
+   * import { w3cwebsocket } from 'websocket';
+   * 
+   * let socket = new WebSocketSubject({
+   *   url: 'ws://localhost:8081',
+   *   WebSocketCtor: w3cwebsocket
+   * });
+   *
+   * let subject = Observable.webSocket('ws://localhost:8081');
+   * subject.subscribe(
+   *    (msg) => console.log('message received: ' + msg),
+   *    (err) => console.log(err),
+   *    () => console.log('complete')
+   *  );
+   * subject.next(JSON.stringify({ op: 'hello' }));
+   *
+   * @param {string | WebSocketSubjectConfig} urlConfigOrSource the source of the websocket as an url or a structure defining the websocket object
    * @return {WebSocketSubject}
    * @static true
    * @name webSocket