Add additional helper methods to annotatorUI service

i
These also now always set new map instances so that the angular
watcher picks up changes without having to do a deep comparison.

h/static/scripts/annotation-ui-service.coffee

@@ -2,6 +2,9 @@
 # attached iframes for display in the sidebar. This covers both tool and
 # rendered state such as selected highlights.
 createAnnotationUI = ->
+  value = (selection) ->
+    if Object.keys(selection).length then selection else null
+
   {
     TOOL_COMMENT: 'comment'
     TOOL_HIGHLIGHT: 'highlight'
@@ -10,8 +13,10 @@ createAnnotationUI = ->
 
     visibleHighlights: false
 
+    # Contains a map of annotation id:true pairs.
     focusedAnnotationMap: null
 
+    # Contains a map of annotation id:true pairs.
     selectedAnnotationMap: null
 
     ###*
@@ -24,7 +29,23 @@ createAnnotationUI = ->
     focusAnnotations: (annotations) ->
       selection = {}
       selection[id] = true for {id} in annotations
-      @focusedAnnotationMap = selection
+      @focusedAnnotationMap = value(selection)
+
+    ###*
+    # @ngdoc method
+    # @name annotationUI.hasSelectedAnnotations
+    # @returns true if there are any selected annotations.
+    ###
+    hasSelectedAnnotations: ->
+      !!@selectedAnnotationMap
+
+    ###*
+    # @ngdoc method
+    # @name annotationUI.isAnnotationSelected
+    # @returns true if the provided annotation is selected.
+    ###
+    isAnnotationSelected: (id) ->
+      !!@selectedAnnotationMap?[id]
 
     ###*
     # @ngdoc method
@@ -36,7 +57,7 @@ createAnnotationUI = ->
     selectAnnotations: (annotations) ->
       selection = {}
       selection[id] = true for {id} in annotations
-      @selectedAnnotationMap = selection
+      @selectedAnnotationMap = value(selection)
 
     ###*
     # @ngdoc method
@@ -46,13 +67,13 @@ createAnnotationUI = ->
     # selectedAnnotationMap if not present otherwise removes them.
     ###
     xorSelectedAnnotations: (annotations) ->
-      selection = @selectedAnnotationMap or {}
+      selection = angular.extend({}, @selectedAnnotationMap)
       for {id} in annotations
         if selection[id]
           delete selection[id]
         else
           selection[id] = true
-      @selectedAnnotationMap = selection
+      @selectedAnnotationMap = value(selection)
 
     ###*
     # @ngdoc method
@@ -61,8 +82,19 @@ createAnnotationUI = ->
     # @description removes an annotation from the current selection.
     ###
     removeSelectedAnnotation: (annotation) ->
-      return unless @selectedAnnotationMap
-      delete @selectedAnnotationMap[annotation.id]
+      selection = angular.extend({}, @selectedAnnotationMap)
+      if selection
+        delete selection[annotation.id]
+        @selectedAnnotationMap = value(selection)
+
+    ###*
+    # @ngdoc method
+    # @name annotationUI.clearSelectedAnnotations()
+    # @returns nothing
+    # @description removes all annotations from the current selection.
+    ###
+    clearSelectedAnnotations: ->
+      @selectedAnnotationMap = null
   }
 
 angular.module('h').factory('annotationUI', createAnnotationUI)

tests/js/annotation-ui-service-test.coffee

@@ -22,6 +22,38 @@ describe 'AnnotationUI', ->
         2: true, 3: true
       })
 
+    it 'does not modify the original map object', ->
+      orig = annotationUI.focusedAnnotationMap = {1: true}
+      annotationUI.focusAnnotations([{id: 2}, {id: 3}])
+      assert.notEqual(annotationUI.focusedAnnotationMap, orig)
+
+    it 'nulls the map if no annotations are focused', ->
+      orig = annotationUI.focusedAnnotationMap = {1: true}
+      annotationUI.focusAnnotations([])
+      assert.isNull(annotationUI.focusedAnnotationMap)
+
+  describe '.hasSelectedAnnotations', ->
+    it 'returns true if there are any selected annotations', ->
+      annotationUI.selectedAnnotationMap = {1: true}
+      assert.isTrue(annotationUI.hasSelectedAnnotations())
+
+    it 'returns false if there are no selected annotations', ->
+      annotationUI.selectedAnnotationMap = null
+      assert.isFalse(annotationUI.hasSelectedAnnotations())
+
+  describe '.isAnnotationSelected', ->
+    it 'returns true if the id provided is selected', ->
+      annotationUI.selectedAnnotationMap = {1: true}
+      assert.isTrue(annotationUI.isAnnotationSelected(1))
+
+    it 'returns false if the id provided is not selected', ->
+      annotationUI.selectedAnnotationMap = {1: true}
+      assert.isFalse(annotationUI.isAnnotationSelected(2))
+
+    it 'returns false if there are no selected annotations', ->
+      annotationUI.selectedAnnotationMap = null
+      assert.isFalse(annotationUI.isAnnotationSelected(1))
+
   describe '.selectAnnotations()', ->
     it 'adds the passed annotations to the selectedAnnotationMap', ->
       annotationUI.selectAnnotations([{id: 1}, {id: 2}, {id: 3}])
@@ -36,6 +68,16 @@ describe 'AnnotationUI', ->
         2: true, 3: true
       })
 
+    it 'does not modify the original map object', ->
+      orig = annotationUI.selectedAnnotationMap = {1: true}
+      annotationUI.selectAnnotations([{id: 2}, {id: 3}])
+      assert.notEqual(annotationUI.selectedAnnotationMap, orig)
+
+    it 'nulls the map if no annotations are selected', ->
+      orig = annotationUI.selectedAnnotationMap = {1: true}
+      annotationUI.selectAnnotations([])
+      assert.isNull(annotationUI.selectedAnnotationMap)
+
   describe '.xorSelectedAnnotations()', ->
     it 'adds annotations missing from the selectedAnnotationMap', ->
       annotationUI.selectedAnnotationMap = {1: true, 2: true}
@@ -43,10 +85,21 @@ describe 'AnnotationUI', ->
       assert.deepEqual(annotationUI.selectedAnnotationMap, {
         1: true, 2: true, 3: true, 4: true
       })
+
     it 'removes annotations already in the selectedAnnotationMap', ->
-      annotationUI.selectedAnnotationMap = {1: true, 2: true}
+      annotationUI.selectedAnnotationMap = {1: true, 3: true}
       annotationUI.xorSelectedAnnotations([{id: 1}, {id: 2}])
-      assert.deepEqual(annotationUI.selectedAnnotationMap, {})
+      assert.deepEqual(annotationUI.selectedAnnotationMap, 2:true, 3: true)
+
+    it 'does not modify the original map object', ->
+      orig = annotationUI.selectedAnnotationMap = {1: true}
+      annotationUI.xorSelectedAnnotations([{id: 2}, {id: 3}])
+      assert.notEqual(annotationUI.selectedAnnotationMap, orig)
+
+    it 'nulls the map if no annotations are selected', ->
+      orig = annotationUI.selectedAnnotationMap = {1: true}
+      annotationUI.xorSelectedAnnotations([id: 1])
+      assert.isNull(annotationUI.selectedAnnotationMap)
 
   describe '.removeSelectedAnnotation', ->
     it 'removes an annotation from the selectedAnnotationMap', ->
@@ -55,3 +108,19 @@ describe 'AnnotationUI', ->
       assert.deepEqual(annotationUI.selectedAnnotationMap, {
         1: true, 3: true
       })
+
+    it 'does not modify the original map object', ->
+      orig = annotationUI.selectedAnnotationMap = {1: true}
+      annotationUI.removeSelectedAnnotation(id: 1)
+      assert.notEqual(annotationUI.selectedAnnotationMap, orig)
+
+    it 'nulls the map if no annotations are selected', ->
+      orig = annotationUI.selectedAnnotationMap = {1: true}
+      annotationUI.removeSelectedAnnotation(id: 1)
+      assert.isNull(annotationUI.selectedAnnotationMap)
+
+  describe '.clearSelectedAnnotations', ->
+    it 'removes all annotations from the selection', ->
+      annotationUI.selectedAnnotationMap = {1: true, 2: true, 3: true}
+      annotationUI.clearSelectedAnnotations()
+      assert.isNull(annotationUI.selectedAnnotationMap)