Add a string formatter (#2087)

* add StringFormat to formats
 fix #2086

platform/features/conductor/core/bundle.js

@@ -28,6 +28,7 @@ define([
     "./src/ui/TimeOfInterestController",
     "./src/ui/ConductorAxisDirective",
     "./src/ui/NumberFormat",
+    "./src/ui/StringFormat",
     "text!./res/templates/time-conductor.html",
     "text!./res/templates/mode-selector/mode-selector.html",
     "text!./res/templates/mode-selector/mode-menu.html",
@@ -41,6 +42,7 @@ define([
     TimeOfInterestController,
     ConductorAxisDirective,
     NumberFormat,
+    StringFormat,
     timeConductorTemplate,
     modeSelectorTemplate,
     modeMenuTemplate,
@@ -145,6 +147,10 @@ define([
                 {
                     "key": "number",
                     "implementation": NumberFormat
+                },
+                {
+                    "key": "string",
+                    "implementation": StringFormat
                 }
             ]
         }

platform/features/conductor/core/src/ui/StringFormat.js

@@ -0,0 +1,53 @@
+/*****************************************************************************
+ * Open MCT, Copyright (c) 2014-2018, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+
+define([], function () {
+
+    /**
+     * Formatter for basic strings.
+     *
+     * @implements {Format}
+     * @constructor
+     * @memberof platform/commonUI/formats
+     */
+    function StringFormat() {
+        this.key = 'string';
+    }
+
+    StringFormat.prototype.format = function (string) {
+        if (typeof string === 'string') {
+            return string;
+        } else {
+            return '' + string;
+        }
+    };
+
+    StringFormat.prototype.parse = function (string) {
+        return string;
+    };
+
+    StringFormat.prototype.validate = function (string) {
+        return typeof string === 'string';
+    };
+
+    return StringFormat;
+});