Bump to v4.4.0.

_baseFlatten.js

@@ -8,12 +8,12 @@ import isArrayLikeObject from './isArrayLikeObject';
  *
  * @private
  * @param {Array} array The array to flatten.
- * @param {boolean} [isDeep] Specify a deep flatten.
+ * @param {number} depth The maximum recursion depth.
  * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
  * @param {Array} [result=[]] The initial result value.
  * @returns {Array} Returns the new flattened array.
  */
-function baseFlatten(array, isDeep, isStrict, result) {
+function baseFlatten(array, depth, isStrict, result) {
   result || (result = []);
 
   var index = -1,
@@ -21,11 +21,11 @@ function baseFlatten(array, isDeep, isStrict, result) {
 
   while (++index < length) {
     var value = array[index];
-    if (isArrayLikeObject(value) &&
+    if (depth > 0 && isArrayLikeObject(value) &&
         (isStrict || isArray(value) || isArguments(value))) {
-      if (isDeep) {
+      if (depth > 1) {
         // Recursively flatten arrays (susceptible to call stack limits).
-        baseFlatten(value, isDeep, isStrict, result);
+        baseFlatten(value, depth - 1, isStrict, result);
       } else {
         arrayPush(result, value);
       }