select2/src/js/jquery.select2.js

define([
  'jquery',
  'require',

  './select2/core',
  './select2/defaults'
], function ($, require, Select2, Defaults) {
  // Force jQuery.mousewheel to be loaded if it hasn't already
  require('jquery.mousewheel');

  if ($.fn.select2 == null) {
    // All methods that should return the element
    var thisMethods = ['open', 'close', 'destroy'];

    $.fn.select2 = function (options) {
      options = options || {};

      if (typeof options === 'object') {
        this.each(function () {
          var instanceOptions = $.extend({}, options, true);

          var instance = new Select2($(this), instanceOptions);
        });

        return this;
      } else if (typeof options === 'string') {
        var instance = this.data('select2');
        var args = Array.prototype.slice.call(arguments, 1);

        var ret = instance[options](args);

        // Check if we should be returning `this`
        if ($.inArray(options, thisMethods) > -1) {
          return this;
        }

        return ret;
      } else {
        throw new Error('Invalid arguments for Select2: ' + options);
      }
    };
  }

  if ($.fn.select2.defaults == null) {
    $.fn.select2.defaults = Defaults;
  }

  return Select2;
});