strict_filters/strict_variables when creating engine

src/util/underscore.js

@@ -25,27 +25,75 @@ function forOwn(object, iteratee) {
     return object;
 }
 
-function assign(dst, src) {
-    dst = dst || {};
+/*
+ * Assigns own enumerable string keyed properties of source objects to the destination object. 
+ * Source objects are applied from left to right. 
+ * Subsequent sources overwrite property assignments of previous sources.  
+ *
+ * Note: This method mutates object and is loosely based on Object.assign.
+ *
+ * @param {Object} object The destination object.
+ * @param {...Object} sources The source objects.
+ * @return {Object} Returns object.
+ */
+function assign(object) {
+    object = isObject(object) ? object : {};
+    var srcs = Array.prototype.slice.call(arguments, 1);
+    srcs.forEach(function(src) {
+        _assignBinary(object, src);
+    });
+    return object;
+}
+
+function _assignBinary(dst, src) {
+    if (!dst) return dst;
     forOwn(src, function(v, k) {
         dst[k] = v;
     });
     return dst;
 }
 
+
 function isArray(value) {
     return value instanceof Array;
 }
 
-function echo(prefix){
+function echo(prefix) {
     return v => {
         console.log('[' + prefix + ']', v);
         return v;
     };
 }
 
+function uniq(arr) {
+    var u = {},
+        a = [];
+    for (var i = 0, l = arr.length; i < l; ++i) {
+        if (u.hasOwnProperty(arr[i])) {
+            continue;
+        }
+        a.push(arr[i]);
+        u[arr[i]] = 1;
+    }
+    return a;
+}
+
+/*
+ * Checks if value is the language type of Object. 
+ * (e.g. arrays, functions, objects, regexes, new Number(0), and new String(''))
+ * @param {any} value The value to check.
+ * @return {Boolean} Returns true if value is an object, else false.
+ */
+function isObject(value) {
+    return value !== null && typeof value === 'object';
+}
+
 exports.isString = isString;
 exports.isArray = isArray;
+exports.isObject = isObject;
+
 exports.forOwn = forOwn;
 exports.assign = assign;
+exports.uniq = uniq;
+
 exports.echo = echo;