From c02c2d3b2c090ad3d0490633b4e5f5df5e7de92e Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Sat, 25 Aug 2012 21:50:08 -0700
Subject: [PATCH] Optimize `_.intersection`, move `largeSize` default to
 `largeArraySize`, and cleanup `_.where`.

Former-commit-id: 9eaea7922623f1bd69f2b18578468a6fc9ba13fc
---
 build.js             |  2 +-
 build/pre-compile.js |  4 ++--
 lodash.js            | 29 +++++++++++++++++------------
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/build.js b/build.js
index acbd22a95..57aeea51b 100755
--- a/build.js
+++ b/build.js
@@ -186,7 +186,7 @@
     'identity': [],
     'indexOf': ['sortedIndex'],
     'initial': [],
-    'intersection': ['every', 'indexOf'],
+    'intersection': ['indexOf'],
     'invoke': [],
     'isArguments': [],
     'isArray': [],
diff --git a/build/pre-compile.js b/build/pre-compile.js
index aa65069ad..db395d6d2 100644
--- a/build/pre-compile.js
+++ b/build/pre-compile.js
@@ -7,6 +7,8 @@
 
   /** Used to minify variables embedded in compiled strings */
   var compiledVars = [
+    'argsIndex',
+    'argsLength',
     'callback',
     'collection',
     'concat',
@@ -36,8 +38,6 @@
     // lesser used variables
     'accumulator',
     'args',
-    'argsIndex',
-    'argsLength',
     'arrayLikeClasses',
     'ArrayProto',
     'bind',
diff --git a/lodash.js b/lodash.js
index febc06a51..4e163dd9f 100644
--- a/lodash.js
+++ b/lodash.js
@@ -47,6 +47,9 @@
   /** Used to generate unique IDs */
   var idCounter = 0;
 
+  /** Used by `cachedContains` as the default size when optimizations are enabled for large arrays */
+  var largeArraySize = 30;
+
   /** Used to restore the original `_` reference in `noConflict` */
   var oldDash = window._;
 
@@ -548,7 +551,7 @@
     fromIndex || (fromIndex = 0);
 
     var length = array.length,
-        isLarge = (length - fromIndex) >= (largeSize || 30),
+        isLarge = (length - fromIndex) >= (largeSize || largeArraySize),
         cache = isLarge ? {} : array;
 
     if (isLarge) {
@@ -2365,15 +2368,15 @@
   var where = createIterator(filterIteratorOptions, {
     'args': 'collection, properties',
     'top':
-      'var pass, prop, propIndex, props = [];\n' +
+      'var props = [];\n' +
       'forIn(properties, function(value, prop) { props.push(prop) });\n' +
       'var propsLength = props.length',
     'inLoop':
-      'for (pass = true, propIndex = 0; propIndex < propsLength; propIndex++) {\n' +
+      'for (var prop, pass = true, propIndex = 0; propIndex < propsLength; propIndex++) {\n' +
       '  prop = props[propIndex];\n' +
       '  if (!(pass = value[prop] === properties[prop])) break\n' +
       '}\n' +
-      'if (pass) result.push(value)'
+      'pass && result.push(value)'
   });
 
   /*--------------------------------------------------------------------------*/
@@ -2597,17 +2600,19 @@
       return result;
     }
     var value,
+        argsLength = arguments.length,
+        cache = [],
         index = -1,
-        length = array.length,
-        others = slice.call(arguments, 1),
-        cache = [];
+        length = array.length;
 
-    while (++index < length) {
+    array: while (++index < length) {
       value = array[index];
-      if (indexOf(result, value) < 0 &&
-          every(others, function(other, index) {
-            return (cache[index] || (cache[index] = cachedContains(other)))(value);
-          })) {
+      if (indexOf(result, value) < 0) {
+        for (var argsIndex = 1; argsIndex < argsLength; argsIndex++) {
+          if (!(cache[argsIndex] || (cache[argsIndex] = cachedContains(arguments[argsIndex])))(value)) {
+            continue array;
+          }
+        }
         result.push(value);
       }
     }