Only copy own properties

merge.js

@@ -10,7 +10,7 @@
 ;(function(isNode) {
 
 	/**
-	 * Merge one or more objects 
+	 * Merge one or more objects
 	 * @param bool? clone
 	 * @param mixed,... arguments
 	 * @return object
@@ -23,7 +23,7 @@
 	}, publicName = 'merge';
 
 	/**
-	 * Merge two or more objects recursively 
+	 * Merge two or more objects recursively
 	 * @param bool? clone
 	 * @param mixed,... arguments
 	 * @return object
@@ -85,13 +85,17 @@
 
 		for (var key in extend) {
 
-			if (typeOf(base[key]) === 'object' && typeOf(extend[key]) === 'object') {
+			if (extend.hasOwnProperty(key)) {
 
-				base[key] = merge_recursive(base[key], extend[key]);
+				if (typeOf(base[key]) === 'object' && typeOf(extend[key]) === 'object') {
 
-			} else {
+					base[key] = merge_recursive(base[key], extend[key]);
 
-				base[key] = extend[key];
+				} else {
+
+					base[key] = extend[key];
+
+				}
 
 			}
 
@@ -128,15 +132,19 @@
 
 			for (var key in item) {
 
-				var sitem = clone ? Public.clone(item[key]) : item[key];
+				if (item.hasOwnProperty(key)) {
 
-				if (recursive) {
+					var sitem = clone ? Public.clone(item[key]) : item[key];
 
-					result[key] = merge_recursive(result[key], sitem);
+					if (recursive) {
 
-				} else {
+						result[key] = merge_recursive(result[key], sitem);
+
+					} else {
+
+						result[key] = sitem;
 
-					result[key] = sitem;
+					}
 
 				}
 

tests/tests.js

@@ -1,3 +1,7 @@
+function Foo(){}
+
+Foo.prototype.bar = 1;
+
 test('merge', function() {
 
 	deepEqual(
@@ -48,6 +52,14 @@ test('merge', function() {
 
 	);
 
+	deepEqual(
+
+		merge({}, new Foo()),
+
+		{}
+
+	);
+
 });
 
 test('merge (clone)', function() {
@@ -141,6 +153,14 @@ test('merge.recursive', function() {
 
 	);
 
+	deepEqual(
+
+		merge.recursive({}, new Foo()),
+
+		{}
+
+	);
+
 });
 
 test('merge.recursive (clone)', function() {