From c044f18bcdda4aad995f622b818524c8fbf0a7b5 Mon Sep 17 00:00:00 2001
From: CJ Kihlbom <cj@elabs.se>
Date: Sun, 18 Mar 2012 14:34:17 -0700
Subject: [PATCH] Add Collection#sortBy method

Sorts the collection by the given attribute of each item.

Collection#sortBy will trigger a 'update' event on the collection, making views update automatically.

Example:

  @collection = new Serenade.Collection([{name:'Jonas'}, {name:'CJ'}])
  @collection.sortBy('name')
  @collection.get(0) # Returns the `{name:'CJ'}` object
---
 spec/collection.spec.coffee | 12 ++++++++++++
 src/collection.coffee       |  2 ++
 2 files changed, 14 insertions(+)

diff --git a/spec/collection.spec.coffee b/spec/collection.spec.coffee
index 56beed1..9d45129 100644
--- a/spec/collection.spec.coffee
+++ b/spec/collection.spec.coffee
@@ -42,6 +42,18 @@ describe 'Serenade.Collection', ->
       @collection.sort()
       expect(@collection).toHaveReceivedEvent('update')
 
+  describe '#sortBy', ->
+    it 'updates the order of the items in the collection', ->
+      item1 = {name: 'CJ', age: 30}
+      item2 = {name: 'Anders', age: 37}
+      @collection.update([item1, item2])
+
+      @collection.sortBy('age')
+      expect(@collection.list).toEqual([item1, item2])
+
+      @collection.sortBy('name')
+      expect(@collection.list).toEqual([item2, item1])
+
   describe '#push', ->
     it 'adds an item to the collection', ->
       @collection.push('g')
diff --git a/src/collection.coffee b/src/collection.coffee
index 08e02da..1c10b8f 100644
--- a/src/collection.coffee
+++ b/src/collection.coffee
@@ -28,6 +28,8 @@ class exports.Collection
   sort: (fun) ->
     @list.sort(fun)
     @trigger("update", @list)
+  sortBy: (attribute) ->
+    @sort((a, b) -> if a[attribute] < b[attribute] then -1 else 1)
   forEach: (fun) ->
     forEach(@list, fun)
   map: (fun) ->