From 3aa40d4df64c27fb71bf8c0cd2ee4b336ddd9d31 Mon Sep 17 00:00:00 2001
From: jdalton <john.david.dalton@gmail.com>
Date: Sun, 1 Mar 2015 01:22:00 -0800
Subject: [PATCH] Simplify `baseFlatten` and always provide a `fromIndex`.

---
 lodash.src.js | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/lodash.src.js b/lodash.src.js
index b7c00fc2b..cecf66386 100644
--- a/lodash.src.js
+++ b/lodash.src.js
@@ -2144,13 +2144,13 @@
      *
      * @private
      * @param {Array} array The array to flatten.
-     * @param {boolean} [isDeep] Specify a deep flatten.
-     * @param {boolean} [isStrict] Restrict flattening to arrays and `arguments` objects.
-     * @param {number} [fromIndex=0] The index to start from.
+     * @param {boolean} isDeep Specify a deep flatten.
+     * @param {boolean} isStrict Restrict flattening to arrays and `arguments` objects.
+     * @param {number} fromIndex The index to start from.
      * @returns {Array} Returns the new flattened array.
      */
     function baseFlatten(array, isDeep, isStrict, fromIndex) {
-      var index = fromIndex == null ? -1 : (fromIndex - 1),
+      var index = fromIndex - 1,
           length = array.length,
           resIndex = -1,
           result = [];
@@ -2161,7 +2161,7 @@
         if (isObjectLike(value) && isLength(value.length) && (isArray(value) || isArguments(value))) {
           if (isDeep) {
             // Recursively flatten arrays (susceptible to call stack limits).
-            value = baseFlatten(value, isDeep, isStrict);
+            value = baseFlatten(value, isDeep, isStrict, 0);
           }
           var valIndex = -1,
               valLength = value.length;
@@ -4666,7 +4666,7 @@
       if (guard && isIterateeCall(array, isDeep, guard)) {
         isDeep = false;
       }
-      return length ? baseFlatten(array, isDeep) : [];
+      return length ? baseFlatten(array, isDeep, false, 0) : [];
     }
 
     /**
@@ -4684,7 +4684,7 @@
      */
     function flattenDeep(array) {
       var length = array ? array.length : 0;
-      return length ? baseFlatten(array, true) : [];
+      return length ? baseFlatten(array, true, false, 0) : [];
     }
 
     /**
@@ -5344,7 +5344,7 @@
      * // => [1, 2, 4]
      */
     function union() {
-      return baseUniq(baseFlatten(arguments, false, true));
+      return baseUniq(baseFlatten(arguments, false, true, 0));
     }
 
     /**