Bump to v4.0.0.

assign.js

@@ -0,0 +1,39 @@
+import copyObject from './internal/copyObject';
+import createAssigner from './internal/createAssigner';
+import keys from './keys';
+
+/**
+ * Assigns own enumerable 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`](https://mdn.io/Object/assign).
+ *
+ * @static
+ * @memberOf _
+ * @category Object
+ * @param {Object} object The destination object.
+ * @param {...Object} [sources] The source objects.
+ * @returns {Object} Returns `object`.
+ * @example
+ *
+ * function Foo() {
+ *   this.c = 3;
+ * }
+ *
+ * function Bar() {
+ *   this.e = 5;
+ * }
+ *
+ * Foo.prototype.d = 4;
+ * Bar.prototype.f = 6;
+ *
+ * _.assign({ 'a': 1 }, new Foo, new Bar);
+ * // => { 'a': 1, 'c': 3, 'e': 5 }
+ */
+var assign = createAssigner(function(object, source) {
+  copyObject(source, keys(source), object);
+});
+
+export default assign;