options.js

define([
  'require',
  'jquery',
  './defaults',
  './utils'
], function (require, $, Defaults, Utils) {
  function Options (options, $element) {
    this.options = options;
    this.jQuery1x = false;
    this.elementData = null;
    
    // Html already attempted to be read from html5-* attribs.
    this.attemptedHtml5DataItems = {};

    if ($element != null) {
      // Override `options` with html5 data-* attribs if any.
      this.fromElement($element);
      
      // Prefetch properties. 
      for(var propertyName in Defaults.defaults) {
        this.get(propertyName);
     }
      
    }

    this.options = Defaults.apply(this.options);

    if ($element && $element.is('input')) {
      var InputCompat = require(this.get('amdBase') + 'compat/inputData');

      this.options.dataAdapter = Utils.Decorate(
        this.options.dataAdapter,
        InputCompat
      );
    }
  }

  Options.prototype.fromElement = function ($e) {
    var excludedData = ['select2'];

    if (this.options.multiple == null) {
      this.options.multiple = $e.prop('multiple');
    }

    if (this.options.disabled == null) {
      this.options.disabled = $e.prop('disabled');
    }

    if (this.options.language == null) {
      if ($e.prop('lang')) {
        this.options.language = $e.prop('lang').toLowerCase();
      } else if ($e.closest('[lang]').prop('lang')) {
        this.options.language = $e.closest('[lang]').prop('lang');
      }
    }

    if (this.options.dir == null) {
      if ($e.prop('dir')) {
        this.options.dir = $e.prop('dir');
      } else if ($e.closest('[dir]').prop('dir')) {
        this.options.dir = $e.closest('[dir]').prop('dir');
      } else {
        this.options.dir = 'ltr';
      }
    }

    $e.prop('disabled', this.options.disabled);
    $e.prop('multiple', this.options.multiple);

    if (Utils.GetData($e[0], 'select2Tags')) {
      if (this.options.debug && window.console && console.warn) {
        console.warn(
          'Select2: The `data-select2-tags` attribute has been changed to ' +
          'use the `data-data` and `data-tags="true"` attributes and will be ' +
          'removed in future versions of Select2.'
        );
      }

      Utils.StoreData($e[0], 'data', Utils.GetData($e[0], 'select2Tags'));
      Utils.StoreData($e[0], 'tags', true);
    }

    if (Utils.GetData($e[0], 'ajaxUrl')) {
      if (this.options.debug && window.console && console.warn) {
        console.warn(
          'Select2: The `data-ajax-url` attribute has been changed to ' +
          '`data-ajax--url` and support for the old attribute will be removed' +
          ' in future versions of Select2.'
        );
      }

      $e.attr('ajax--url', Utils.GetData($e[0], 'ajaxUrl'));
      Utils.StoreData($e[0], 'ajax-Url', Utils.GetData($e[0], 'ajaxUrl'));
	  
    }

    var dataset = {};

    // Prefer the element's `dataset` attribute if it exists
    // jQuery 1.x does not correctly handle data attributes with multiple dashes
    if ($.fn.jquery && $.fn.jquery.substr(0, 2) == '1.' && $e[0].dataset) {
      this.jQuery1x = true;
      dataset = $.extend(true, {}, $e[0].dataset, Utils.GetData($e[0]));
    } else {
      dataset = Utils.GetData($e[0]);
    }

    var data = $.extend(true, {}, dataset);

    data = Utils._convertData(data);

    for (var key in data) {
      if ($.inArray(key, excludedData) > -1) {
        continue;
      }

      if ($.isPlainObject(this.options[key])) {
        $.extend(this.options[key], data[key]);
      } else {
        this.options[key] = data[key];
      }
    }

    // Store normalized element data for later retrieval.
    this.elementData = Utils._convertData($e.data());

    return this;
  };

  Options.prototype.get = function (key) {

    if (!this.elementData || this.attemptedHtml5DataItems[key]) {
      return this.options[key];
    }
    // If the option value is stored in html5 data-* attribs,
    // fetch the value and store it for performance.
    if (!this.jQuery1x) {      
      // For jQuery 1.x, the html5 data-* attribs have already 
      // been parsed above.
      // Read all attribs that start with `key`.  
      for (var dataKey in this.elementData) {
        if (dataKey.indexOf(key) === 0) {
          
          if ($.isPlainObject(this.options[key])) {
            $.extend(this.options[key], this.elementData[dataKey]);
          } else {
            this.options[key] = this.elementData[dataKey];
          }
        }
      }
    }
    // Mark as attempted.
    this.attemptedHtml5DataItems[key] = true; 
    return this.options[key];
  };

  Options.prototype.set = function (key, val) {
    this.options[key] = val;
  };

  return Options;
});