From 36db80d45f867f197a8d23e41dd91e0bdbb9512f Mon Sep 17 00:00:00 2001
From: Piotr Sarnacki <drogus@gmail.com>
Date: Tue, 18 Feb 2014 10:00:33 +0100
Subject: [PATCH] Add Ember.computed.limit and use it in LimitedArray

arrayComputed was added recently in order to make array computations
easier. Using arrayComputed we can improve LimitedArray which now uses
an isolated multipurpose Ember.computed.limit.
---
 assets/scripts/lib/ext/ember/computed.js      | 26 ++++++++
 .../scripts/lib/travis/limited_array.coffee   | 63 ++-----------------
 .../spec/unit/limited_array_spec.coffee       |  3 +-
 assets/scripts/travis.coffee                  |  1 +
 4 files changed, 35 insertions(+), 58 deletions(-)
 create mode 100644 assets/scripts/lib/ext/ember/computed.js

diff --git a/assets/scripts/lib/ext/ember/computed.js b/assets/scripts/lib/ext/ember/computed.js
new file mode 100644
index 00000000..089f8fe1
--- /dev/null
+++ b/assets/scripts/lib/ext/ember/computed.js
@@ -0,0 +1,26 @@
+Ember.computed.limit = function(dependentKey, limitKey) {
+  var options = {
+    addedItem: function(array, item, changeMeta, instanceMeta) {
+      var limit = Ember.get(this, limitKey);
+      if (changeMeta.index < limit) {
+        array.insertAt(changeMeta.index, item);
+        if (Ember.get(array, "length") > limit) {
+          array.popObject();
+        }
+      }
+      return array;
+    },
+    removedItem: function(array, item, changeMeta, instanceMeta) {
+      var limit = Ember.get(this, limitKey);
+      if (changeMeta.index < limit && changeMeta.index < Ember.get(array, 'length')) {
+        array.removeAt(changeMeta.index, 1);
+        var toPush = changeMeta.arrayChanged.objectAt(limit);
+        if (toPush) {
+          array.pushObject(toPush);
+        }
+      }
+      return array;
+    }
+  };
+  return Ember.arrayComputed(dependentKey, limitKey, options);
+};
diff --git a/assets/scripts/lib/travis/limited_array.coffee b/assets/scripts/lib/travis/limited_array.coffee
index c6baaddc..f5f9941f 100644
--- a/assets/scripts/lib/travis/limited_array.coffee
+++ b/assets/scripts/lib/travis/limited_array.coffee
@@ -1,17 +1,7 @@
 Travis.LimitedArray = Em.ArrayProxy.extend
   limit: 10
   isLoadedBinding: 'content.isLoaded'
-
-  init: ->
-    @_super.apply this, arguments
-
-  arrangedContent: (->
-    content = @get('content')
-    if @get('disabled')
-      content
-    else if content
-      content.slice(0, @get('limit'))
-  ).property('content', 'limit', 'disabled')
+  arrangedContent: Ember.computed.limit('content', 'limit')
 
   totalLength: (->
     @get('content.length')
@@ -21,54 +11,13 @@ Travis.LimitedArray = Em.ArrayProxy.extend
     totalLength = @get('totalLength')
     limit       = @get('limit')
 
-    if @get('disabled') || totalLength <= limit
-      0
-    else
-      totalLength - limit
-  ).property('totalLength', 'limit', 'disabled')
+    left = totalLength - limit
+    if left < 0 then 0 else left
+  ).property('totalLength', 'limit')
 
   isMore: (->
-    !@get('disabled') && @get('leftLength') > 0
+    @get('leftLength') > 0
   ).property('leftLength')
 
   showAll: ->
-    @set 'disabled', true
-
-  contentArrayWillChange: (array, index, removedCount, addedCount) ->
-    @_super.apply this, arguments
-
-    return if @get('disabled')
-
-    if removedCount
-      arrangedContent = @get 'arrangedContent'
-      removedObjects = array.slice(index, index + removedCount);
-      arrangedContent.removeObjects(removedObjects)
-
-  contentArrayDidChange: (array, index, removedCount, addedCount) ->
-    @_super.apply this, arguments
-
-    return if @get('disabled')
-
-    limit = @get('limit')
-
-    if addedCount
-      if index < limit
-        addedObjects = array.slice(index, index + addedCount)
-        @get('arrangedContent').replace(index, 0, addedObjects)
-
-    @balanceArray()
-
-  balanceArray: ->
-    limit  = @get 'limit'
-    arrangedContent = @get 'arrangedContent'
-    length = arrangedContent.get 'length'
-    content = @get 'content'
-
-    if length > limit
-      arrangedContent.replace(limit, length - limit)
-    else if length < limit && content.get('length') > length
-      count = limit - length
-      while count > 0
-        if next = content.find( (object) -> !arrangedContent.contains(object) )
-          arrangedContent.pushObject(next)
-        count -= 1
+    @set 'limit', Infinity
diff --git a/assets/scripts/spec/unit/limited_array_spec.coffee b/assets/scripts/spec/unit/limited_array_spec.coffee
index 818bbecc..8c482234 100644
--- a/assets/scripts/spec/unit/limited_array_spec.coffee
+++ b/assets/scripts/spec/unit/limited_array_spec.coffee
@@ -41,7 +41,8 @@ test 'allows to expand array to show all items', ->
   content = [1, 2, 3]
   array = Travis.LimitedArray.create content: content, limit: 2
 
-  array.showAll()
+  Ember.run ->
+    array.showAll()
 
   equal( array.get('length'), 3)
   deepEqual( array.toArray(), [1, 2, 3])
diff --git a/assets/scripts/travis.coffee b/assets/scripts/travis.coffee
index f01a0e0b..dea8798d 100644
--- a/assets/scripts/travis.coffee
+++ b/assets/scripts/travis.coffee
@@ -1,5 +1,6 @@
 require 'ext/jquery'
 require 'ext/ember/namespace'
+require 'ext/ember/computed'
 require 'app'
 
 window.ENV ||= {}