gistfile1.js

  /**
   * SELECT2
   *
   * Renders Select2 - jQuery based replacement for select boxes
   *
   * Requires an 'options.values' value on the schema.
   *  Can be an array of options, a function that calls back with the array of options, a string of HTML
   *  or a Backbone collection. If a collection, the models must implement a toString() method
   */
  Backbone.Form.editors.Select2 = Backbone.Form.editors.Base.extend({		 

    tagName: 'select',
		
    events: {
      'change': function(event) {
        this.trigger('change', this);
      },
      'focus':  function(event) {
        this.trigger('focus', this);
      },
      'blur':   function(event) {
        this.trigger('blur', this);
      }
    },

    initialize: function(options) {
      Backbone.Form.editors.Base.prototype.initialize.call(this, options);

      if (!this.schema || !this.schema.options.values) throw "Missing required 'schema.options.values'";
    },

    render: function() {
	var self = this;
      	this.setOptions(this.schema.options.values);
	if (this.schema.options.multiple) {
		this.$el.attr('multiple','multiple');
	}
	setTimeout(function () {self.$el.select2({width:'resolve'})},0);			
			
      return this;
    },

    /**
     * Sets the options that populate the <select>
     *
     * @param {Mixed} options
     */
    setOptions: function(options) {
      var self = this;

      //If a collection was passed, check if it needs fetching
      if (options instanceof Backbone.Collection) {
        var collection = options;

        //Don't do the fetch if it's already populated
        if (collection.length > 0) {
          this.renderOptions(options);
        } else {
          collection.fetch({
            success: function(collection) {
              self.renderOptions(options);
            }
          });
        }
      }

      //If a function was passed, run it to get the options
      else if (_.isFunction(options)) {
        options(function(result) {
          self.renderOptions(result);
        }, self);
      }

      //Otherwise, ready to go straight to renderOptions
      else {
        this.renderOptions(options);
      }
    },

    /**
     * Adds the <option> html to the DOM
     * @param {Mixed}   Options as a simple array e.g. ['option1', 'option2']
     *                      or as an array of objects e.g. [{val: 543, label: 'Title for object 543'}]
     *                      or as a string of <option> HTML to insert into the <select>
     */
    renderOptions: function(options) {
      var $select = this.$el,
          html;

      html = this._getOptionsHtml(options);

      //Insert options
      $select.html(html);

      //Select correct option
      this.setValue(this.value);
    },

    _getOptionsHtml: function(options) {
      var html;
      //Accept string of HTML
      if (_.isString(options)) {
        html = options;
      }

      //Or array
      else if (_.isArray(options)) {
        html = this._arrayToHtml(options);
      }

      //Or Backbone collection
      else if (options instanceof Backbone.Collection) {
        html = this._collectionToHtml(options);
      }

      else if (_.isFunction(options)) {
        var newOptions;
        
        options(function(opts) {
          newOptions = opts;
        }, this);
        
        html = this._getOptionsHtml(newOptions);
      }

      return html;
    },

    getValue: function() {
      return this.$el.val();
    },

    setValue: function(value) {
      this.$el.val(value);
    },

    focus: function() {
      if (this.hasFocus) return;

      this.$el.focus();
    },

    blur: function() {
      if (!this.hasFocus) return;

      this.$el.blur();
    },

    /**
     * Transforms a collection into HTML ready to use in the renderOptions method
     * @param {Backbone.Collection}
     * @return {String}
     */
    _collectionToHtml: function(collection) {
      //Convert collection to array first
      var array = [];
      collection.each(function(model) {
        array.push({ val: model.id, label: model.toString() });
      });

      //Now convert to HTML
      var html = this._arrayToHtml(array);

      return html;
    },

    /**
     * Create the <option> HTML
     * @param {Array}   Options as a simple array e.g. ['option1', 'option2']
     *                      or as an array of objects e.g. [{val: 543, label: 'Title for object 543'}]
     * @return {String} HTML
     */
    _arrayToHtml: function(array) {
      var html = [];

      //Generate HTML
      _.each(array, function(option) {
        if (_.isObject(option)) {
          if (option.group) {
            html.push('<optgroup label="'+option.group+'">');
            html.push(this._getOptionsHtml(option.options))
            html.push('</optgroup>');
          } else {
            var val = (option.val || option.val === 0) ? option.val : '';
            html.push('<option value="'+val+'">'+option.label+'</option>');
          }
        }
        else {
          html.push('<option>'+option+'</option>');
        }
      }, this);

      return html.join('');
    }

  });