Fix note highlight being lost after real time update

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/33483

app/assets/javascripts/notes.js

@@ -56,6 +56,7 @@ const normalizeNewlines = function(str) {
       this.toggleCommitList = this.toggleCommitList.bind(this);
       this.postComment = this.postComment.bind(this);
       this.clearFlashWrapper = this.clearFlash.bind(this);
+      this.onHashChange = this.onHashChange.bind(this);
 
       this.notes_url = notes_url;
       this.note_ids = note_ids;
@@ -127,7 +128,9 @@ const normalizeNewlines = function(str) {
       $(document).on('ajax:success', '.js-main-target-form', this.resetMainTargetForm);
       $(document).on('ajax:complete', '.js-main-target-form', this.reenableTargetFormSubmitButton);
       // when a key is clicked on the notes
-      return $(document).on('keydown', '.js-note-text', this.keydownNoteText);
+      $(document).on('keydown', '.js-note-text', this.keydownNoteText);
+      // When the URL fragment/hash has changed, `#note_xxx`
+      return $(window).on('hashchange', this.onHashChange);
     };
 
     Notes.prototype.cleanBinding = function() {
@@ -148,6 +151,7 @@ const normalizeNewlines = function(str) {
       $(document).off('ajax:success', '.js-main-target-form');
       $(document).off('ajax:success', '.js-discussion-note-form');
       $(document).off('ajax:complete', '.js-main-target-form');
+      $(window).off('hashchange', this.onHashChange);
     };
 
     Notes.initCommentTypeToggle = function (form) {
@@ -298,8 +302,27 @@ const normalizeNewlines = function(str) {
     Notes.prototype.setupNewNote = function($note) {
       // Update datetime format on the recent note
       gl.utils.localTimeAgo($note.find('.js-timeago'), false);
+
       this.collapseLongCommitList();
       this.taskList.init();
+
+      // This stops the note highlight, #note_xxx`, from being removed after real time update
+      // The `:target` selector does not re-evaluate after we replace element in the DOM
+      Notes.updateNoteTargetSelector($note);
+      this.$noteToCleanHighlight = $note;
+    };
+
+    Notes.prototype.onHashChange = function() {
+      if (this.$noteToCleanHighlight) {
+        Notes.updateNoteTargetSelector(this.$noteToCleanHighlight);
+      }
+
+      this.$noteToCleanHighlight = null;
+    };
+
+    Notes.updateNoteTargetSelector = function($note) {
+      const hash = gl.utils.getLocationHash();
+      $note.toggleClass('target', hash && $note.filter(`#${hash}`).length > 0);
     };
 
     /*
@@ -597,13 +620,12 @@ const normalizeNewlines = function(str) {
       $noteEntityEl = $(noteEntity.html);
       $noteEntityEl.addClass('fade-in-full');
       this.revertNoteEditForm($targetNote);
-      gl.utils.localTimeAgo($('.js-timeago', $noteEntityEl));
       $noteEntityEl.renderGFM();
-      $noteEntityEl.find('.js-task-list-container').taskList('enable');
       // Find the note's `li` element by ID and replace it with the updated HTML
       $note_li = $('.note-row-' + noteEntity.id);
 
       $note_li.replaceWith($noteEntityEl);
+      this.setupNewNote($noteEntityEl);
 
       if (typeof gl.diffNotesCompileComponents !== 'undefined') {
         gl.diffNotesCompileComponents();

spec/javascripts/notes_spec.js

@@ -126,6 +126,7 @@ import '~/notes';
         const deferred = $.Deferred();
         spyOn($, 'ajax').and.returnValue(deferred.promise());
         spyOn(this.notes, 'revertNoteEditForm');
+        spyOn(this.notes, 'setupNewNote');
 
         $('.js-comment-button').click();
         deferred.resolve(noteEntity);
@@ -136,6 +137,46 @@ import '~/notes';
         this.notes.updateNote(updatedNote, $targetNote);
 
         expect(this.notes.revertNoteEditForm).toHaveBeenCalledWith($targetNote);
+        expect(this.notes.setupNewNote).toHaveBeenCalled();
+      });
+    });
+
+    describe('updateNoteTargetSelector', () => {
+      const hash = 'note_foo';
+      let $note;
+
+      beforeEach(() => {
+        $note = $(`<div id="${hash}"></div>`);
+        spyOn($note, 'filter').and.callThrough();
+        spyOn($note, 'toggleClass').and.callThrough();
+      });
+
+      it('sets target when hash matches', () => {
+        spyOn(gl.utils, 'getLocationHash');
+        gl.utils.getLocationHash.and.returnValue(hash);
+
+        Notes.updateNoteTargetSelector($note);
+
+        expect($note.filter).toHaveBeenCalledWith(`#${hash}`);
+        expect($note.toggleClass).toHaveBeenCalledWith('target', true);
+      });
+
+      it('unsets target when hash does not match', () => {
+        spyOn(gl.utils, 'getLocationHash');
+        gl.utils.getLocationHash.and.returnValue('note_doesnotexist');
+
+        Notes.updateNoteTargetSelector($note);
+
+        expect($note.toggleClass).toHaveBeenCalledWith('target', false);
+      });
+
+      it('unsets target when there is not a hash fragment anymore', () => {
+        spyOn(gl.utils, 'getLocationHash');
+        gl.utils.getLocationHash.and.returnValue(null);
+
+        Notes.updateNoteTargetSelector($note);
+
+        expect($note.toggleClass).toHaveBeenCalledWith('target', null);
       });
     });
 
@@ -189,9 +230,13 @@ import '~/notes';
           Notes.isUpdatedNote.and.returnValue(true);
           const $note = $('<div>');
           $notesList.find.and.returnValue($note);
+          const $newNote = $(note.html);
+          Notes.animateUpdateNote.and.returnValue($newNote);
+
           Notes.prototype.renderNote.call(notes, note, null, $notesList);
 
           expect(Notes.animateUpdateNote).toHaveBeenCalledWith(note.html, $note);
+          expect(notes.setupNewNote).toHaveBeenCalledWith($newNote);
         });
 
         describe('while editing', () => {