rx-winjs/src/websocket.js

Library for composing asynchronous and event-based operations in JavaScript extending the Windows WinJS library

     /**
     * Creates a WebSocket Subject with a given URL, protocol and an optional observer for the open event.
     * 
     * @example
     *  var socket = Rx.DOM.fromWebSocket('http://localhost:8080', 'stock-protocol', function(e) { ... });
     *  var socket = Rx.DOM.fromWebSocket('http://localhost:8080', 'stock-protocol', observer);
     *
     * @param {String} url The URL of the WebSocket.
     * @param {String} protocol The protocol of the WebSocket.
     * @param {Function|Observer} [observerOrOnNext] An optional Observer or onNext function to capture the open event.
     * @returns {Subject} An observable sequence wrapping a WebSocket.
     */
    Rx.WinJS.fromWebSocket = function (url, protocol, observerOrOnNext) {
        var socket = new window.WebSocket(url, protocol);

        var observable = observableCreate(function (obs) {
            if (observerOrOnNext) {
                socket.onopen = function (openEvent) {
                    if (typeof observerOrOnNext === 'function') {
                        observerOrOnNext(openEvent);
                    } else if (observerOrOnNext.onNext) {
                        observerOrOnNext.onNext(openEvent);
                    }
                };
            }

            socket.onmessage = function (data) {
                obs.onNext(data);
            };

            socket.onerror = function (err) {
                obs.onError(err);
            };

            socket.onclose = function () {
                obs.onCompleted();
            };

            return function () {
                socket.close();
            };
        });

        var observer = observerCreate(function (data) {
            if (socket.readyState === WebSocket.OPEN) {
                socket.send(data);
            }
        });

        return Subject.create(observer, observable);
    };