Initialize the selected annotations from app settings

When the sidebar loads in a page with a '#annotations'
URL fragment, the 'annotations' setting will be
passed through to the client as `settings.annotations`.

Use this to initialize the selection so that
the annotation specified by '#annotations:<ID>' is
selected when the client loads.

h/static/scripts/annotation-ui.js

@@ -2,12 +2,20 @@
 
 function value(selection) {
   if (Object.keys(selection).length) {
-    return selection;
+    return Object.freeze(selection);
   } else {
     return null;
   }
 }
 
+function initialSelection(settings) {
+  var selection = {};
+  if (settings.annotations) {
+    selection[settings.annotations] = true;
+  }
+  return value(selection);
+}
+
 /**
  * Stores the UI state of the annotator in connected clients.
  *
@@ -17,7 +25,9 @@ function value(selection) {
  * - The state of the bucket bar
  *
  */
-module.exports = function () {
+
+// @ngInject
+module.exports = function (settings) {
   return {
     visibleHighlights: false,
 
@@ -25,7 +35,7 @@ module.exports = function () {
     focusedAnnotationMap: null,
 
     // Contains a map of annotation id:true pairs.
-    selectedAnnotationMap: null,
+    selectedAnnotationMap: initialSelection(settings),
 
     /**
      * @ngdoc method
@@ -62,17 +72,19 @@ module.exports = function () {
     },
 
     /**
-     * @ngdoc method
-     * @name annotationUI.selectAnnotations
-     * @returns nothing
-     * @description Takes an array of annotation objects and uses them to
-     * set the selectedAnnotationMap property.
+     * Set the currently selected annotation IDs.
+     *
+     * @param {Array<string|{id:string}>} annotations - Annotations or IDs
+     *        of annotations to select.
      */
     selectAnnotations: function (annotations) {
       var selection = {};
-      for (var i = 0, annotation; i < annotations.length; i++) {
-        annotation = annotations[i];
-        selection[annotation.id] = true;
+      for (var i = 0; i < annotations.length; i++) {
+        if (typeof annotations[i] === 'string') {
+          selection[annotations[i]] = true;
+        } else {
+          selection[annotations[i].id] = true;
+        }
       }
       this.selectedAnnotationMap = value(selection);
     },

h/static/scripts/test/annotation-ui-test.js

 'use strict';
 
+var annotationUIFactory = require('../annotation-ui');
+
 describe('annotationUI', function () {
   var annotationUI;
 
   beforeEach(function () {
-    annotationUI = require('../annotation-ui')();
+    annotationUI = annotationUIFactory({});
+  });
+
+  describe('initialization', function () {
+    it('does not set a selection when settings.annotations is null', function () {
+      assert.isFalse(annotationUI.hasSelectedAnnotations());
+    });
+
+    it('sets the selection when settings.annotations is set', function () {
+      annotationUI = annotationUIFactory({annotations: 'testid'});
+      assert.deepEqual(annotationUI.selectedAnnotationMap, {
+        testid: true,
+      });
+    });
   });
 
   describe('.focusAnnotations()', function () {

h/static/scripts/test/app-controller-test.js

@@ -15,7 +15,6 @@ describe('AppController', function () {
   var fakeLocation = null;
   var fakeParams = null;
   var fakeSession = null;
-  var fakeSettings = null;
   var fakeGroups = null;
   var fakeRoute = null;
   var fakeSettings = null;