Bump to v4.0.0.

forIn.js

@@ -0,0 +1,35 @@
+import baseFor from './internal/baseFor';
+import keysIn from './keysIn';
+import toFunction from './internal/toFunction';
+
+/**
+ * Iterates over own and inherited enumerable properties of an object invoking
+ * `iteratee` for each property. The iteratee is invoked with three arguments:
+ * (value, key, object). Iteratee functions may exit iteration early by explicitly
+ * returning `false`.
+ *
+ * @static
+ * @memberOf _
+ * @category Object
+ * @param {Object} object The object to iterate over.
+ * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @returns {Object} Returns `object`.
+ * @example
+ *
+ * function Foo() {
+ *   this.a = 1;
+ *   this.b = 2;
+ * }
+ *
+ * Foo.prototype.c = 3;
+ *
+ * _.forIn(new Foo, function(value, key) {
+ *   console.log(key);
+ * });
+ * // => logs 'a', 'b', then 'c' (iteration order is not guaranteed)
+ */
+function forIn(object, iteratee) {
+  return object == null ? object : baseFor(object, toFunction(iteratee), keysIn);
+}
+
+export default forIn;