Hide `Focus mode` on issue boards

app/assets/javascripts/boards/boards_bundle.js

@@ -141,6 +141,7 @@ $(() => {
       modal: ModalStore.store,
       store: Store.state,
       isFullscreen: false,
+      focusModeAvailable: gl.utils.convertPermissionToBoolean($boardApp.dataset.focusModeAvailable),
     },
     watch: {
       disabled() {
@@ -177,6 +178,8 @@ $(() => {
         }
       },
       toggleFocusMode() {
+        if (!this.focusModeAvailable) { return; }
+
         $(this.$refs.toggleFocusModeButton).tooltip('hide');
         issueBoardsContent.classList.toggle('is-focused');
 
@@ -206,6 +209,7 @@ $(() => {
           aria-label="Toggle focus mode"
           title="Toggle focus mode"
           ref="toggleFocusModeButton"
+          v-if="focusModeAvailable"
           @click="toggleFocusMode">
           <span v-show="isFullscreen">
             ${collapseIcon}

app/helpers/boards_helper.rb

 module BoardsHelper
+  prepend EE::BoardsHelper
+
   def board_data
     board = @board || @boards.first
 

app/helpers/ee/boards_helper.rb

+module EE
+  module BoardsHelper
+    def board_data
+      super.merge(focus_mode_available: @project.feature_available?(:issue_board_focus_mode).to_s)
+    end
+  end
+end

spec/features/boards/ee/boards_spec.rb

+require 'spec_helper'
+
+describe 'issue boards', feature: true, js: true do
+  let(:user) { create(:user) }
+  let(:project) { create(:empty_project, :public) }
+  let!(:board) { create(:board, project: project) }
+
+  before do
+    project.add_developer(user)
+    login_as(user)
+  end
+
+  context 'issue board focus mode' do
+    it 'shows the button when the feature is enabled' do
+      stub_licensed_features(issue_board_focus_mode: true)
+
+      visit_board_page
+
+      expect(page).to have_link('Toggle focus mode')
+    end
+
+    it 'hides the button when the feature is enabled' do
+      stub_licensed_features(issue_board_focus_mode: false)
+
+      visit_board_page
+
+      expect(page).not_to have_link('Toggle focus mode')
+    end
+  end
+
+  def visit_board_page
+    visit namespace_project_boards_path(project.namespace, project)
+    wait_for_requests
+  end
+end