diff --git a/node_modules/mdl-ext/es/utils/string-utils.js b/node_modules/mdl-ext/es/utils/string-utils.js
new file mode 100644
index 0000000..ab0045a
--- /dev/null
+++ b/node_modules/mdl-ext/es/utils/string-utils.js
@@ -0,0 +1,114 @@
+'use strict';
+
+/**
+ * @license
+ * Copyright 2016 Leif Olsen. All Rights Reserved.
+ *
+ * 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.
+ */
+
+/**
+ * A javascript utility for conditionally creating a list of strings.
+ * The function takes any number of arguments which can be a string or object.
+ * Inspired by (but not copied from) JedWatson/classnames, https://github.com/JedWatson/classnames
+ *
+ * @param  {*} args the strings and/or objects to
+ * @return {Array} a list of strings
+ * @example
+ * // Returns ['foo', 'bar', 'baz', 'quux']
+ * stringList(', ', 'foo', { bar: true, duck: false }, 'baz', { quux: true });
+ * @example see the tests for more examples
+ */
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.stringList = exports.randomString = exports.joinStrings = undefined;
+
+var _keys = require('babel-runtime/core-js/object/keys');
+
+var _keys2 = _interopRequireDefault(_keys);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+var stringList = function stringList() {
+  for (var _len = arguments.length, args = Array(_len), _key = 0; _key < _len; _key++) {
+    args[_key] = arguments[_key];
+  }
+
+  var isString = function isString(str) {
+    return str != null && typeof str === 'string';
+  };
+
+  var flatten = function flatten(list) {
+    return list.reduce(function (a, b) {
+      return a.concat(Array.isArray(b) ? flatten(b) : b);
+    }, []);
+  };
+
+  var objectToStrings = function objectToStrings(arg) {
+    return (0, _keys2.default)(arg).filter(function (key) {
+      return arg[key];
+    }).map(function (key) {
+      return key;
+    });
+  };
+
+  return args.filter(function (arg) {
+    return !!arg;
+  }).map(function (arg) {
+    return isString(arg) ? arg : objectToStrings(arg);
+  }).reduce(function (result, arg) {
+    return result.concat(Array.isArray(arg) ? flatten(arg) : arg);
+  }, []);
+};
+
+/**
+ * A simple javascript utility for conditionally joining strings together.
+ * The function takes a delimiter string and any number of arguments which can be a string or object.
+ *
+ * @param delimiter delimiter to separate joined strings
+ * @param  {*} args the strings and/or objects to join
+ * @return {String} the joined strings
+ * @example
+ * // Returns 'foo, bar, baz, quux'
+ * joinStrings(', ', 'foo', { bar: true, duck: false }, 'baz', { quux: true });
+ * @example see the tests for more examples
+ */
+var joinStrings = function joinStrings() {
+  for (var _len2 = arguments.length, args = Array(_len2 > 1 ? _len2 - 1 : 0), _key2 = 1; _key2 < _len2; _key2++) {
+    args[_key2 - 1] = arguments[_key2];
+  }
+
+  var delimiter = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : ' ';
+  return stringList.apply(undefined, args).join(delimiter);
+};
+
+/**
+ * Generates a random string with a given length
+ * @param n {Integer} length of generated string
+ * @see http://stackoverflow.com/questions/1349404/generate-random-string-characters-in-javascript
+ * @return {String} the random string
+ * @example
+ * // Returns e.g. 'pd781w0y'
+ * randomString(8);
+ * @example see the tests for more examples
+ */
+var randomString = function randomString() {
+  var n = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 12;
+  return Array(n + 1).join((Math.random().toString(36) + '00000000000000000').slice(2, 18)).slice(0, n);
+};
+
+exports.joinStrings = joinStrings;
+exports.randomString = randomString;
+exports.stringList = stringList;
\ No newline at end of file