segmentio/analytics.js open source script load

load_analytics.js

    // Create a queue, but don't obliterate an existing one!
    window.analytics = window.analytics || [];

    // A list of the methods in Analytics.js to stub.
    window.analytics.methods = ['identify', 'group', 'track',
    'page', 'pageview', 'alias', 'ready', 'on', 'once', 'off',
    'trackLink', 'trackForm', 'trackClick', 'trackSubmit'];

    // Define a factory to create stubs. These are placeholders
    // for methods in Analytics.js so that you never have to wait
    // for it to load to actually record data. The `method` is
    // stored as the first argument, so we can replay the data.
    window.analytics.factory = function(method){
        return function(){
          var args = Array.prototype.slice.call(arguments);
          args.unshift(method);
          window.analytics.push(args);
          return window.analytics;
        };
    };

    // For each of our methods, generate a queueing stub.
    for (var i = 0; i < window.analytics.methods.length; i++) {
        var key = window.analytics.methods[i];
        window.analytics[key] = window.analytics.factory(key);
    }

    // Define a method to load Analytics.js
        // and that will be sure to only ever load it once.
    analytics.load = function(callback) {
        if (document.getElementById('analytics-js')) return;

        // We make a copy if our dummy object
        window.a = window.analytics

        // Create an async script element
        var script = document.createElement('script');
        script.type = 'text/javascript';
        script.id = 'analytics-js';
        script.async = true;
        //script.src = '/media/js/analytics.js';
        script.src = 'https://raw.githubusercontent.com/segmentio/analytics.js/master/analytics.js'

        script.addEventListener('load', function(e) {
            if (typeof callback === 'function') {
              callback(e);
            }
          }, false);
        // Insert our script next to the first script element.
        var first = document.getElementsByTagName('script')[0];
        first.parentNode.insertBefore(script, first);
    };