Bump to v4.1.0.

_baseFlatten.js

@@ -0,0 +1,39 @@
+var arrayPush = require('./_arrayPush'),
+    isArguments = require('./isArguments'),
+    isArray = require('./isArray'),
+    isArrayLikeObject = require('./isArrayLikeObject');
+
+/**
+ * The base implementation of `_.flatten` with support for restricting flattening.
+ *
+ * @private
+ * @param {Array} array The array to flatten.
+ * @param {boolean} [isDeep] Specify a deep flatten.
+ * @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) {
+  result || (result = []);
+
+  var index = -1,
+      length = array.length;
+
+  while (++index < length) {
+    var value = array[index];
+    if (isArrayLikeObject(value) &&
+        (isStrict || isArray(value) || isArguments(value))) {
+      if (isDeep) {
+        // Recursively flatten arrays (susceptible to call stack limits).
+        baseFlatten(value, isDeep, isStrict, result);
+      } else {
+        arrayPush(result, value);
+      }
+    } else if (!isStrict) {
+      result[result.length] = value;
+    }
+  }
+  return result;
+}
+
+module.exports = baseFlatten;