improve performance of quiz index search box

we were previously re-rendering the list for every model changed. Now we only
render after the filtering is complete.

fixes CNVS-16247

test plan:
  - as a teacher
    - create a course with 30 or more quizzes
    - filter the quizzes using the search box at the top of the index page
    - It should filter the results much faster!!

Change-Id: Iafb0624a4974ff48223b87b2849c12476e098062
Reviewed-on: https://gerrit.instructure.com/43578
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Ryan Taylor <rtaylor@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>

Author: Derek DeVries

app/coffeescripts/views/quizzes/IndexView.coffee

@@ -28,31 +28,17 @@ define [
       @options.hasOpenQuizzes        = @openView.collection.length > 0
       @options.hasSurveys            = @surveyView.collection.length > 0
 
-    collections: ->
+    views: ->
       [
-        @options.assignmentView.collection
-        @options.openView.collection
-        @options.surveyView.collection
+        @options.assignmentView
+        @options.openView
+        @options.surveyView
       ]
 
-    keyUpSearch: =>
-      clearTimeout @onInputTimer
-      @onInputTimer = setTimeout @filterResults, 200
+    keyUpSearch: _.debounce ->
+      @filterResults()
+    , 200
 
     filterResults: =>
-      term = $('#searchTerm').val()
-
-      _.each @collections(), (collection) =>
-        collection.each (model) =>
-          model.set('hidden', !@filter(model, term))
-
-    filter: (model, term) =>
-      return true unless term
-
-      title = model.get('title').toLowerCase()
-      numMatches = 0
-      keys = term.toLowerCase().split(' ')
-      for part in keys
-        #not using match to avoid javascript string to regex oddness
-        numMatches++ if title.indexOf(part) != -1
-      numMatches == keys.length
+      _.each @views(), (view) =>
+        view.filterResults($('#searchTerm').val())

app/coffeescripts/views/quizzes/QuizItemGroupView.coffee

@@ -25,8 +25,27 @@ define [
     isEmpty: ->
       @collection.isEmpty() or @collection.all((m) -> m.get('hidden'))
 
-    attachCollection: ->
-      @collection.on('change:hidden', @render)
+    filterResults: (term) =>
+      anyChanged = false
+      @collection.forEach (model) =>
+        hidden = !@filter(model, term)
+        if !!model.get('hidden') != hidden
+          anyChanged = true
+          model.set('hidden', hidden)
+
+      @render() if anyChanged
+
+    filter: (model, term) =>
+      return true unless term
+
+      title = model.get('title').toLowerCase()
+      numMatches = 0
+      keys = term.toLowerCase().split(' ')
+      for part in keys
+        #not using match to avoid javascript string to regex oddness
+        numMatches++ if title.indexOf(part) != -1
+      numMatches == keys.length
+
 
     render: ->
       super

spec/coffeescripts/views/quizzes/IndexViewSpec.coffee

@@ -125,23 +125,3 @@ define [
     view.filterResults()
     equal view.$el.find('.collectionViewItems li').length, 2
 
-  test 'should filter models with title that doesnt match term', ->
-    view = indexView()
-    model = new Quiz(title: "Foo Name")
-
-    ok  view.filter(model, "name")
-    ok !view.filter(model, "zzz")
-
-  test 'should not use regexp to filter models', ->
-    view = indexView()
-    model = new Quiz(title: "Foo Name")
-
-    ok !view.filter(model, ".*name")
-    ok !view.filter(model, "zzz")
-
-  test 'should filter models with multiple terms', ->
-    view = indexView()
-    model = new Quiz(title: "Foo Name bar")
-
-    ok  view.filter(model, "name bar")
-    ok !view.filter(model, "zzz")

spec/coffeescripts/views/quizzes/QuizItemGroupViewSpec.coffee

@@ -36,13 +36,37 @@ define [
     ok view.isEmpty()
 
 
-  test 'should rerender on :hidden change', ->
+  test 'should filter models with title that doesnt match term', ->
     collection = new QuizCollection([{id: 1}, {id: 2}])
     view = createView(collection)
+    model = new Quiz(title: "Foo Name")
+
+    ok  view.filter(model, "name")
+    ok !view.filter(model, "zzz")
+
+  test 'should not use regexp to filter models', ->
+    collection = new QuizCollection([{id: 1}, {id: 2}])
+    view = createView(collection)
+    model = new Quiz(title: "Foo Name")
+
+    ok !view.filter(model, ".*name")
+    ok !view.filter(model, "zzz")
+
+  test 'should filter models with multiple terms', ->
+    collection = new QuizCollection([{id: 1}, {id: 2}])
+    view = createView(collection)
+    model = new Quiz(title: "Foo Name bar")
+
+    ok  view.filter(model, "name bar")
+    ok !view.filter(model, "zzz")
+
+
+  test 'should rerender on filter change', ->
+    collection = new QuizCollection([{id: 1, title: 'hey'}, {id: 2, title: 'foo'}])
+    view = createView(collection)
     equal view.$el.find('.collectionViewItems li').length, 2
 
-    quiz = collection.get(1)
-    quiz.set('hidden', true)
+    view.filterResults('hey')
     equal view.$el.find('.collectionViewItems li').length, 1
 
   test 'should not render no content message if quizzes are available', ->