lodash/test/ui.js

;(function(window) {
  'use strict';

  /** `QUnit.addEvent` shortcut */
  var addEvent = QUnit.addEvent;

  /** The Lo-Dash build to load */
  var build = (/build=([^&]+)/.exec(location.search) || [])[1];

  /** A flag to determine if RequireJS should be loaded */
  var norequire = /[?&]norequire=true(?:&|$)/.test(location.search);

  /*--------------------------------------------------------------------------*/

  // assign `QUnit.config` properties
  QUnit.config.lodashFilename = build == 'prod'
    ? 'lodash.min'
    : (build == 'custom' ? 'lodash.custom.min' : 'lodash');

  // assign `QUnit.urlParams` properties
  QUnit.extend(QUnit.urlParams, {
    'build': build,
    'norequire': norequire
  });

  // initialize the build dropdown
  addEvent(window, 'load', function() {
    function eventHandler(event) {
      var search = location.search.replace(/^\?|&?(?:build|norequire)=[^&]*&?/g, '');
      if (event.stopPropagation) {
        event.stopPropagation();
      } else {
        event.cancelBubble = true;
      }
      location.href =
        location.href.split('?')[0] + '?' +
        (search ? search + '&' : '') + 'build=' +
        dropdown[dropdown.selectedIndex].value +
        (checkbox.checked ? '&norequire=true' : '');
    }

    function init() {
      var header = document.getElementById('qunit-header');
      if (header) {
        header.appendChild(label1);
        header.appendChild(label2);

        if (build == 'prod') {
          dropdown.selectedIndex = 1;
        } else if (build == 'custom') {
          dropdown.selectedIndex = 2;
        }
        checkbox.checked = norequire;
        addEvent(checkbox, 'click', eventHandler);
        addEvent(dropdown, 'change', eventHandler);
      }
      else {
        setTimeout(init, 15);
      }
    }

    var label1 = document.createElement('label');
    label1.innerHTML =
      '<input name="norequire" type="checkbox">norequire</label>';

    var label2 = document.createElement('label');
    label2.innerHTML =
      '<select name="build">' +
      '<option value="dev">developement</option>' +
      '<option value="prod">production</option>' +
      '<option value="custom">custom</option>' +
      '</select>build';

    var checkbox = label1.firstChild,
        dropdown = label2.firstChild;

    init();
  });

}(this));