OpenROV / openrov-cockpit

src/static/js/app.js

//This is the support file for the /views/index.ejs
$(function() {

    //http://stackoverflow.com/questions/901115/how-can-i-get-query-string-values-in-javascript
    function getParameterByName(name, url) {
        if (!url)
            url = window.location.href;
        name = name.replace(/[\[\]]/g, '\\$&');
        var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
            results = regex.exec(url);
        if (!results)
            return null;
        if (!results[2])
            return '';
        return decodeURIComponent(results[2].replace(/\+/g, ' '));
    }

    function setGetParameter(paramName, paramValue) {
        var url = window.location.href;
        var hash = location.hash;
        url = url.replace(hash, '');
        if (url.indexOf(paramName + '=') >= 0) {
            var prefix = url.substring(0, url.indexOf(paramName));
            var suffix = url.substring(url.indexOf(paramName));
            suffix = suffix.substring(suffix.indexOf('=') + 1);
            suffix = suffix.indexOf('&') >= 0 ? suffix.substring(suffix.indexOf('&')) : '';
            if (paramValue == null) {

It is recommended to use === to compare with null.

                url = prefix + suffix;
            } else {
                url = prefix + paramName + '=' + paramValue + suffix;
            }
        } else {
            if (url.indexOf('?') < 0)
                url += '?' + paramName + '=' + paramValue;
            else
                url += '&' + paramName + '=' + paramValue;
        }
        window.location.href = url + hash;
    }
    var force = getParameterByName('force');
    //resets the pilot position reservation
    force = force == null ? false : true;

It is recommended to use === to compare with null.

    var mc = getParameterByName('mc');
    //forces going to mission control
    var replay = getParameterByName('rp');
    var e = new EventEmitter2();
    e.ThisIsTheOne = true;
    var blacklist = ['CameraRegistration'];
    var lvcCacheJSON = localStorage.getItem('lvc_cache');
    var cacheSeed = {};
    if (lvcCacheJSON !== null) {
        var lvcCache = JSON.parse(lvcCacheJSON);
        var lvcArray = Object.keys(lvcCache);
        lvcArray.forEach(function(key) {
            if (blacklist.includes(key)) {
                return;
            }
            var parms = lvcCache[key];
            //       parms.unshift(key);
            cacheSeed[key] = {
                context: this,
                args: parms
            };
            //     console.log('seeding event:', key);
        });
    }
    e = new window.EventEmiiterStoreAndForward(e, cacheSeed);
    var cockpit = new Cockpit(e);
    var template = $('#t')[0];
    //template.cockpitEventEmitter = cockpit;
    window.cockpit = cockpit;
    template.rovOnline = false;
    if (mc !== null) {
        loadScript('js/missioncontrol.js');
        //$.getScript('js/missioncontrol.js');
        return;
    }
    if (replay !== null) {
        loadScript('js/replay.js');
        //$.getScript('js/missioncontrol.js');
        return;
    }
    var tokenOption = force == false ? localStorage.sessionID : 'reset';

It is recommended to use === to compare with false.

    var appHasStarted = false;
    var handlePageLoaded = function() {
        if (appHasStarted){
            return; //Guard from multiple calls
        }
        appHasStarted = true;
        var socket = window.io.connect(window.location.protocol + '//' + window.location.hostname + ':' + window.location.port, {
            path: '/cockpitsocket',
            query: 'token=' + tokenOption
        });

        socket = new window.SocketIOStoreAndForward(socket);
        // socket=new window.SocketIOEmitter(socket);
        socket.on('error', function(error) {
            if (error == 'Authentication error') {
                console.log('Someone else already logged in to rov Pilot slot, redirecting to mission control');
                setGetParameter('mc', true);
                loadScript('js/missioncontrol.js');
                return;
            }
        });
        socket.on('forced-disconnect', function() {
            window.location.reload();
        });
        var CacheLVC = function(lvcdumpfn, millseconds) {
            var cache = lvcdumpfn();
            localStorage.setItem('lvc_cache', JSON.stringify(cache));
            setTimeout(CacheLVC.bind(this, lvcdumpfn, millseconds), millseconds);
        };
        //plugin hooks
        var bridge = null;
        socket.on('connect', function() {
            console.log('connection or reconnection to ROV established');
            if (bridge !== null) {
                return;
            }
            //Only do the code below once
            socket.emit('request-sessionToken', function(sessionID) {
                if (bridge !== null) {
                    alert('This should not be called');
                }
                localStorage.setItem('sessionID', sessionID);
                bridge = new window.SocketIOtoEmitterBridge(socket, window.cockpit.rov);
                $('#t')[0].rovOnline = true;
                $('#t')[0].userRole = 'Pilot';
                window.cockpit.rov.connection = 'socket.io';
                var lvcCache = {};
                if (lvcCacheJSON !== null) {
                    lvcCache = JSON.parse(lvcCacheJSON);
                }
                //if they forced the session connect, we need to remove the parameter from the URL
                if (force) {
                    setGetParameter('force', null);
                }
                socket.lvcCache = lvcCache;
                //TESTING: Danger, if the serialization takes to long it might look like a hitch to performance every 3 minutes
                CacheLVC(function() {
                    return lvcCache;
                }, 1000 * 10 * 3);
            });
        });
    };

    window.OROV.startApp = handlePageLoaded;

});