Bump to v4.9.0.

_isFlattenable.js

@@ -0,0 +1,15 @@
+define(['./isArguments', './isArray', './isArrayLikeObject'], function(isArguments, isArray, isArrayLikeObject) {
+
+  /**
+   * Checks if `value` is a flattenable `arguments` object or array.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @returns {boolean} Returns `true` if `value` is flattenable, else `false`.
+   */
+  function isFlattenable(value) {
+    return isArrayLikeObject(value) && (isArray(value) || isArguments(value));
+  }
+
+  return isFlattenable;
+});