From 9e6d84fd7eddd5c33df1c318be87f691c870a59f Mon Sep 17 00:00:00 2001
From: Kevin Gin <kevinagin@gmail.com>
Date: Fri, 26 May 2017 17:20:29 -0700
Subject: [PATCH 1/2] optimized map method by specifiying array size up front

---
 xrange.js | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/xrange.js b/xrange.js
index b462b7f..e7d7fc4 100644
--- a/xrange.js
+++ b/xrange.js
@@ -8,18 +8,13 @@
              * Create array by executing `map` on each value.
              */
 
-            var results = [];
+            var results = new Array(this.length);
 
-            var cmp = function (i, finish) {
-                if (start < finish) {
-                    return i < finish;
-                } else {
-                    return i > finish;
-                }
-            };
+            var value = start;
 
-            for (var i = start; cmp(i, finish); i += by) {
-                results.push(callback(i));
+            for (var i = 0; i < this.length; i++) {
+                results[i] = callback(value);
+                value += by;
             }
 
             return results;

From bad7c230942e61d66ae1b2af8c9d74e7756b2ba9 Mon Sep 17 00:00:00 2001
From: Kevin Gin <kevinagin@gmail.com>
Date: Fri, 26 May 2017 17:37:32 -0700
Subject: [PATCH 2/2] added filter and reduce

---
 test/test.js | 15 +++++++++++++++
 xrange.js    | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/test/test.js b/test/test.js
index 6c69858..f3c2b3b 100644
--- a/test/test.js
+++ b/test/test.js
@@ -155,6 +155,21 @@ describe('Test xrange', function () {
                 return each + 1;
             }), zero2three);
         });
+
+        it('filter', function () {
+            assert.deepEqual(xrange(-5, 5).filter(function (each) {
+                return each >= 0 && each <= 3;
+            }), zero2three);
+        });
+
+        it('reduce', function () {
+            assert.equal(xrange(-5, 8).reduce(function (acc, each) {
+                return acc + each;
+            }), 13);
+            assert.equal(xrange(-5, 8).reduce(function (acc, each) {
+                return acc + each;
+            }, 1), 14);
+        });
     });
 });
 
diff --git a/xrange.js b/xrange.js
index e7d7fc4..f1ec2c2 100644
--- a/xrange.js
+++ b/xrange.js
@@ -20,6 +20,37 @@
             return results;
         };
 
+        this.filter = function (callback) {
+            /**
+             * Create array of items that satisfy predicate function
+             */
+
+            var results = [];
+
+            for (var i = start; i < finish; i += by) {
+                if (callback(i)) {
+                    results.push(i);
+                }
+            }
+            return results;
+        };
+
+        this.reduce = function (callback, acc) {
+            /**
+             *  Reduces an xrange by specified callback
+             */
+
+            if (acc === undefined) {
+                acc = start;
+                start += by;
+            }
+
+            for (var i = start; i < finish; i += by) {
+                acc = callback(acc, i);
+            }
+            return acc;
+        };
+
         this.each = this.forEach = function (callback) {
             /**
              * Call `callback` on each item.
@@ -43,6 +74,8 @@
                 return each;
             });
         };
+
+
     };
 
     var factory = function (start, finish, by) {