From 64a5b1d7f7e38c71fb4e6df884a62509fd012930 Mon Sep 17 00:00:00 2001
From: Arpad Borsos <arpad.borsos@googlemail.com>
Date: Fri, 6 Sep 2013 23:34:26 +0200
Subject: [PATCH 1/2] allow grouping by multiple keys at once

---
 Readme.md     | 22 ++++++++++++++++++++++
 index.js      | 22 +++++++++++++++-------
 test/index.js | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 84 insertions(+), 8 deletions(-)

diff --git a/Readme.md b/Readme.md
index 8863bb9..f909434 100644
--- a/Readme.md
+++ b/Readme.md
@@ -51,6 +51,28 @@ groupBy(users, function(user){
 })
 ```
 
+### groupBy(array, [prop1, prop2])
+### groupBy(array, prop1, prop2)
+### groupBy(array, [fn1, fn2])
+### groupBy(array, fn1, fn2)
+
+  Also groups by multiple keys
+
+```js
+groupBy(nodes, 'type', 'version');
+```
+
+yields:
+
+```js
+{ log: 
+   { '1.0.0': [ { type: 'log', version: '1.0.0' } ],
+     '1.1.0': [ { type: 'log', version: '1.1.0' } ],
+     '1.3.0': [ { type: 'log', version: '1.3.0' } ] },
+  app: { '1.0.0': [ { type: 'app', version: '1.0.0' } ],
+         '1.1.0': [ { type: 'app', version: '1.1.0' } ] } }
+```
+
 ## License
 
   MIT
diff --git a/index.js b/index.js
index 70b0220..3b7bd1d 100644
--- a/index.js
+++ b/index.js
@@ -9,21 +9,29 @@ var toFunction = require('to-function');
  * Group `arr` with callback `fn(val, i)`.
  *
  * @param {Array} arr
- * @param {Function|String} fn or prop
+ * @param {Array|Function|String} fn or prop, or array of fn or prop
  * @return {Array}
  * @api public
  */
 
-module.exports = function(arr, fn){
+module.exports = function(arr, fns){
   var ret = {};
   var prop;
-  fn = toFunction(fn);
+  var obj;
+  var fn;
+  fns = {}.toString.call(fns) === '[object Array]' ? fns : [].slice.call(arguments, 1);
+  fns = fns.map(toFunction);
 
   for (var i = 0; i < arr.length; ++i) {
-    prop = fn(arr[i], i);
-    ret[prop] = ret[prop] || [];
-    ret[prop].push(arr[i]);
+    obj = ret;
+    for (var j = 0; j < fns.length; ++j) {
+      fn = fns[j];
+      prop = fn(arr[i], i);
+      obj[prop] = obj[prop] || (j === fns.length - 1 ? [] : {});
+      obj = obj[prop];
+    }
+    obj.push(arr[i]);
   }
 
   return ret;
-};
\ No newline at end of file
+};
diff --git a/test/index.js b/test/index.js
index 8d3f984..197c70a 100644
--- a/test/index.js
+++ b/test/index.js
@@ -18,6 +18,25 @@ describe('groupBy(arr, prop)', function(){
   })
 })
 
+describe('groupBy(arr, prop1, prop2)', function(){
+  it('should group by multiple properties', function () {
+    var ret = groupBy(nodes, 'type', 'version');
+    console.log(ret)
+    Object.keys(ret.log).should.have.length(3);
+    ret.log['1.0.0'].should.have.length(1);
+    ret.app['1.1.0'].should.have.length(1);
+  })
+})
+
+describe('groupBy(arr, [prop1, prop2])', function(){
+  it('should group by multiple properties', function () {
+    var ret = groupBy(nodes, ['type', 'version']);
+    Object.keys(ret.log).should.have.length(3);
+    ret.log['1.0.0'].should.have.length(1);
+    ret.app['1.1.0'].should.have.length(1);
+  })
+})
+
 describe('groupBy(arr, fn)', function(){
   it('should group by the returned property', function(){
     var ret = groupBy(nodes, function(node){
@@ -28,4 +47,31 @@ describe('groupBy(arr, fn)', function(){
     ret['1.1.0'].should.have.length(2);
     ret['1.3.0'].should.have.length(1);
   })
-})
\ No newline at end of file
+})
+
+describe('groupBy(arr, fn1, fn2)', function(){
+  it('should group by the returned properties', function () {
+    var ret = groupBy(nodes, function(node){
+      return node.type;
+    }, function(node){
+      return node.version;
+    });
+    Object.keys(ret.log).should.have.length(3);
+    ret.log['1.0.0'].should.have.length(1);
+    ret.app['1.1.0'].should.have.length(1);
+  })
+})
+
+describe('groupBy(arr, [fn1, fn2])', function(){
+  it('should group by the returned properties', function () {
+    var ret = groupBy(nodes, function(node){
+      return node.type;
+    }, function(node){
+      return node.version;
+    });
+    Object.keys(ret.log).should.have.length(3);
+    ret.log['1.0.0'].should.have.length(1);
+    ret.app['1.1.0'].should.have.length(1);
+  })
+})
+

From 6c7ab1b46823c393f616a1edbb0058d23a0ced95 Mon Sep 17 00:00:00 2001
From: Arpad Borsos <arpad.borsos@googlemail.com>
Date: Fri, 6 Sep 2013 23:40:42 +0200
Subject: [PATCH 2/2] left a console.log in -_-

---
 test/index.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/index.js b/test/index.js
index 197c70a..402ece1 100644
--- a/test/index.js
+++ b/test/index.js
@@ -21,7 +21,6 @@ describe('groupBy(arr, prop)', function(){
 describe('groupBy(arr, prop1, prop2)', function(){
   it('should group by multiple properties', function () {
     var ret = groupBy(nodes, 'type', 'version');
-    console.log(ret)
     Object.keys(ret.log).should.have.length(3);
     ret.log['1.0.0'].should.have.length(1);
     ret.app['1.1.0'].should.have.length(1);