From dea8ad4c49ce2de928b7c38e8c01b6a4001be095 Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Sat, 13 Oct 2012 23:29:51 -0700
Subject: [PATCH] Optimize `_.contains` and `_.omit`.

Former-commit-id: f1d7b5699bae6de90d880fe593531f7d3772924e
---
 lodash.js    | 15 +++++++++++----
 perf/perf.js | 22 ++++++++++++++++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/lodash.js b/lodash.js
index 5599583d5..383600f81 100644
--- a/lodash.js
+++ b/lodash.js
@@ -1743,7 +1743,7 @@
     forIn(object, function(value, key, object) {
       if (isFunc
             ? !callback(value, key, object)
-            : indexOf(props, key) < 0
+            : indexOf(props, key, 1) < 0
           ) {
         result[key] = value;
       }
@@ -1868,9 +1868,16 @@
    * // => true
    */
   function contains(collection, target) {
-    return toString.call(collection) == stringClass
-      ? collection.indexOf(target) > -1
-      : some(collection, function(value) { return value === target; });
+    var length = collection ? collection.length : 0;
+    if (length === +length) {
+      return (toString.call(collection) == stringClass
+        ? collection.indexOf(target)
+        : indexOf(collection, target)
+      ) > -1;
+    }
+    return some(collection, function(value) {
+      return value === target;
+    });
   }
 
   /**
diff --git a/perf/perf.js b/perf/perf.js
index bf8212b7a..ae3ff2c41 100644
--- a/perf/perf.js
+++ b/perf/perf.js
@@ -512,6 +512,28 @@
 
   /*--------------------------------------------------------------------------*/
 
+  suites.push(
+    Benchmark.Suite('`_.contains` iterating an array')
+      .add('Lo-Dash', '\
+        lodash.contains(numbers, 19)'
+      )
+      .add('Underscore', '\
+        _.contains(numbers, 19)'
+      )
+  );
+
+  suites.push(
+    Benchmark.Suite('`_.contains` iterating an object')
+      .add('Lo-Dash', '\
+        lodash.contains(object, 19)'
+      )
+      .add('Underscore', '\
+        _.contains(object, 19)'
+      )
+  );
+
+  /*--------------------------------------------------------------------------*/
+
   suites.push(
     Benchmark.Suite('`_.countBy` with `callback` iterating an array')
       .add('Lo-Dash', '\