Add persistent flash messages

app/assets/javascripts/lib/utils/flash_queue.js

+import _ from 'underscore';
+import createFlash from '~/flash';
+import AccessorUtilities from '~/lib/utils/accessor';
+
+const FLASH_QUEUE_KEY = 'flash-key';
+
+export function popFlashMessage() {
+  const page = $('body').attr('data-page');
+  let savedFlashMessages;
+  let returnVal = false;
+
+  if (!page) {
+    return returnVal;
+  }
+
+  if (AccessorUtilities.isLocalStorageAccessSafe()) {
+    savedFlashMessages = JSON.parse(window.localStorage.getItem(FLASH_QUEUE_KEY));
+    const queuedMessage = _.findWhere(savedFlashMessages, { bodyData: page });
+    if (queuedMessage) {
+      const queuedMessageIndex = _.findIndex(savedFlashMessages, { bodyData: page });
+      createFlash(queuedMessage.message, queuedMessage.type);
+      savedFlashMessages.splice(queuedMessageIndex, 1);
+      window.localStorage.setItem(FLASH_QUEUE_KEY, JSON.stringify(savedFlashMessages));
+    }
+    returnVal = true;
+  }
+
+  return returnVal;
+}
+
+export function saveFlashMessage(bodyData, message, type) {
+  let savedFlashMessages;
+
+  if (AccessorUtilities.isLocalStorageAccessSafe()) {
+    savedFlashMessages = JSON.parse(window.localStorage.getItem(FLASH_QUEUE_KEY));
+    if (!savedFlashMessages) {
+      savedFlashMessages = [];
+    }
+    savedFlashMessages.push({
+      bodyData,
+      message,
+      type,
+    });
+    window.localStorage.setItem(FLASH_QUEUE_KEY, JSON.stringify(savedFlashMessages));
+  }
+}

app/assets/javascripts/main.js

@@ -33,6 +33,7 @@ import './milestone_select';
 import './projects_dropdown';
 import './render_gfm';
 import initBreadcrumbs from './breadcrumb';
+import { popFlashMessage } from './lib/utils/flash_queue';
 
 import initDispatcher from './dispatcher';
 
@@ -262,4 +263,5 @@ document.addEventListener('DOMContentLoaded', () => {
   }
 
   initDispatcher();
+  popFlashMessage();
 });

app/assets/javascripts/pages/milestones/shared/components/promote_milestone_modal.vue

 <script>
   import axios from '~/lib/utils/axios_utils';
   import createFlash from '~/flash';
+  import { saveFlashMessage } from '~/lib/utils/flash_queue';
   import GlModal from '~/vue_shared/components/gl_modal.vue';
   import { redirectTo } from '~/lib/utils/url_utility';
   import { s__, sprintf } from '~/locale';
@@ -36,7 +37,10 @@
         return axios.post(this.url)
           .then((response) => {
             eventHub.$emit('promoteMilestoneModal.requestFinished', { milestoneUrl: this.url, successful: true });
-            redirectTo(response.request.responseURL);
+            const responseURL = new URL(response.request.responseURL);
+            const bodyData = responseURL.searchParams.get('body_data');
+            saveFlashMessage(bodyData, `${this.milestoneTitle} promoted to group milestone`, 'notice');
+            redirectTo(`${responseURL.protocol}//${responseURL.host}${responseURL.pathname}`);
           })
           .catch((error) => {
             eventHub.$emit('promoteMilestoneModal.requestFinished', { milestoneUrl: this.url, successful: false });

app/assets/javascripts/pages/projects/labels/components/promote_label_modal.vue

 <script>
   import axios from '~/lib/utils/axios_utils';
+  import { saveFlashMessage } from '~/lib/utils/flash_queue';
   import createFlash from '~/flash';
   import GlModal from '~/vue_shared/components/gl_modal.vue';
   import { redirectTo } from '~/lib/utils/url_utility';
@@ -50,7 +51,10 @@
         return axios.post(this.url)
           .then((response) => {
             eventHub.$emit('promoteLabelModal.requestFinished', { labelUrl: this.url, successful: true });
-            redirectTo(response.request.responseURL);
+            const responseURL = new URL(response.request.responseURL);
+            const bodyData = responseURL.searchParams.get('body_data');
+            saveFlashMessage(bodyData, `${this.labelTitle} promoted to group label`, 'notice');
+            redirectTo(`${responseURL.protocol}//${responseURL.host}${responseURL.pathname}`);
           })
           .catch((error) => {
             eventHub.$emit('promoteLabelModal.requestFinished', { labelUrl: this.url, successful: false });

app/controllers/projects/labels_controller.rb

 class Projects::LabelsController < Projects::ApplicationController
   include ToggleSubscriptionAction
+  include FlashHelper
 
   before_action :check_issuables_available!
   before_action :label, only: [:edit, :update, :destroy, :promote]
@@ -114,7 +115,7 @@ class Projects::LabelsController < Projects::ApplicationController
 
       respond_to do |format|
         format.html do
-          redirect_to(project_labels_path(@project), status: 303)
+          redirect_to(project_labels_path(@project, body_data: get_body_data_page(project_labels_path(@project))), status: 303)
         end
         format.js
       end

app/controllers/projects/milestones_controller.rb

 class Projects::MilestonesController < Projects::ApplicationController
   include MilestoneActions
+  include FlashHelper
 
   before_action :check_issuables_available!
   before_action :milestone, only: [:edit, :update, :destroy, :show, :merge_requests, :participants, :labels, :promote]
@@ -70,8 +71,8 @@ class Projects::MilestonesController < Projects::ApplicationController
   end
 
   def promote
-    promoted_milestone = Milestones::PromoteService.new(project, current_user).execute(milestone)
-    redirect_to group_milestone_path(project.group, promoted_milestone.iid), status: 303
+    Milestones::PromoteService.new(project, current_user).execute(milestone)
+    redirect_to project_milestones_path(project, body_data: get_body_data_page(project_milestones_path(project))), status: 303
   rescue Milestones::PromoteService::PromoteMilestoneError => error
     redirect_to milestone, alert: error.message
   end

app/helpers/flash_helper.rb

+module FlashHelper
+  def get_body_data_page(path)
+    return unless path.empty? == false
+
+    path_controller = Rails.application.routes.recognize_path(path)
+    [path_controller[:controller].split('/'), path_controller[:action]].compact.join(':')
+  end
+end

spec/controllers/projects/labels_controller_spec.rb

@@ -133,7 +133,7 @@ describe Projects::LabelsController do
       it 'gives access' do
         post :promote, namespace_id: project.namespace.to_param, project_id: project, id: label_1.to_param
 
-        expect(response).to redirect_to(namespace_project_labels_path)
+        expect(response.location).to include(namespace_project_labels_path)
       end
 
       it 'promotes the label' do

spec/controllers/projects/milestones_controller_spec.rb

@@ -98,9 +98,7 @@ describe Projects::MilestonesController do
       it 'shows group milestone' do
         post :promote, namespace_id: project.namespace.id, project_id: project.id, id: milestone.iid
 
-        group_milestone = assigns(:milestone)
-
-        expect(response).to redirect_to(group_milestone_path(project.group, group_milestone.iid))
+        expect(response.location).to include(project_milestones_path(project))
       end
     end