[#2792] Update the formatInitialValue() method

Select2 3.0 supports an asynchronous formatter.

ckan/public/base/javascript/modules/autocomplete.js

@@ -185,18 +185,27 @@ this.ckan.module('autocomplete', function (jQuery, _) {
 
     /* Callback function that parses the initial field value.
      *
-     * element - The initialized input element wrapped in jQuery.
+     * element  - The initialized input element wrapped in jQuery.
+     * callback - A callback to run once the formatting is complete.
      *
      * Returns a term object or an array depending on the type.
      */
-    formatInitialValue: function (element) {
+    formatInitialValue: function (element, callback) {
       var value = jQuery.trim(element.val() || '');
+      var formatted;
 
       if (this.options.tags) {
-        return jQuery.map(value.split(","), this.formatTerm);
+        formatted = jQuery.map(value.split(","), this.formatTerm);
       } else {
-        return this.formatTerm(value);
+        formatted = this.formatTerm(value);
       }
+
+      // Select2 v3.0 supports a callback for async calls.
+      if (typeof callback === 'function') {
+        callback(formatted);
+      }
+
+      return formatted;
     },
 
     /* Callback triggered when the select2 plugin needs to make a request.

ckan/public/base/test/spec/modules/autocomplete.spec.js

@@ -197,16 +197,30 @@ describe('ckan.modules.AutocompleteModule()', function () {
     });
   });
 
-  describe('.formatInitialValue()', function () {
-    it('should return an item object with id and text properties', function () {
+  describe('.formatInitialValue(element, callback)', function () {
+    beforeEach(function () {
+      this.callback = sinon.spy();
+    });
+
+    it('should pass an item object with id and text properties into the callback', function () {
       var target = jQuery('<input value="test"/>');
-      assert.deepEqual(this.module.formatInitialValue(target), {id: 'test', text: 'test'});
+
+      this.module.formatInitialValue(target, this.callback);
+      assert.calledWith(this.callback, {id: 'test', text: 'test'});
     });
 
-    it('should return an array of properties if options.tags is true', function () {
+    it('should pass an array of properties into the callback if options.tags is true', function () {
       this.module.options.tags = true;
       var target = jQuery('<input />', {value: "test, test"});
-      assert.deepEqual(this.module.formatInitialValue(target), [{id: 'test', text: 'test'}, {id: 'test', text: 'test'}]);
+
+      this.module.formatInitialValue(target, this.callback);
+      assert.calledWith(this.callback, [{id: 'test', text: 'test'}, {id: 'test', text: 'test'}]);
+    });
+
+    it('should return the value if no callback is provided (to support select2 v2.1)', function () {
+      var target = jQuery('<input value="test"/>');
+
+      assert.deepEqual(this.module.formatInitialValue(target), {id: 'test', text: 'test'});
     });
   });