Move getFriendlyDisplayName to RoomMember class. Add more utlity functions.

lib/utils.js

@@ -53,6 +53,52 @@ module.exports.map = function(array, fn) {
     return results;
 };
 
+/**
+ * Applies a filter function to the given array.
+ * @param {Array} array The array to apply the function to.
+ * @param {Function} fn The function that will be invoked for each element in
+ * the array. It should return true to keep the element. The function signature
+ * looks like <code>fn(element, index, array){...}</code>.
+ * @return {Array} A new array with the results of the function.
+ */
+module.exports.filter = function(array, fn) {
+    var results = [];
+    for (var i = 0; i < array.length; i++) {
+        if (fn(array[i], i, array)) {
+            results.push(results);
+        }
+    }
+    return results;
+};
+
+/**
+ * Get the keys for an object. Same as <code>Object.keys()</code>.
+ * @param {Object} obj The object to get the keys for.
+ * @return {string[]} The keys of the object.
+ */
+module.exports.keys = function(obj) {
+    var keys = [];
+    for (var key in obj) {
+        if (!obj.hasOwnProperty(key)) { continue; }
+        keys.push(key);
+    }
+    return keys;
+};
+
+/**
+ * Get the values for an object.
+ * @param {Object} obj The object to get the values for.
+ * @return {Array<*>} The values of the object.
+ */
+module.exports.values = function(obj) {
+    var values = [];
+    for (var key in obj) {
+        if (!obj.hasOwnProperty(key)) { continue; }
+        values.push(obj[key]);
+    }
+    return values;
+};
+
 /**
  * Checks if the given thing is a function.
  * @param {*} value The thing to check.