Merge branch 'flash-es6-module' into 'master'

Flash is now a ES6 module

See merge request gitlab-org/gitlab-ce!14626

74 files changed, 454 insertions, 203 deletions

diff --git a/app/assets/javascripts/awards_handler.js b/app/assets/javascripts/awards_handler.js
index 4f01345ee3b..622764107ad 100644
--- a/app/assets/javascripts/awards_handler.js
+++ b/app/assets/javascripts/awards_handler.js
@@ -1,8 +1,8 @@
 /* eslint-disable class-methods-use-this */
-/* global Flash */
 import _ from 'underscore';
 import Cookies from 'js-cookie';
 import { isInIssuePage, updateTooltipTitle } from './lib/utils/common_utils';
+import Flash from './flash';
 
 const animationEndEventString = 'animationend webkitAnimationEnd MSAnimationEnd oAnimationEnd';
 const transitionEndEventString = 'transitionend webkitTransitionEnd oTransitionEnd MSTransitionEnd';
diff --git a/app/assets/javascripts/blob/balsamiq_viewer.js b/app/assets/javascripts/blob/balsamiq_viewer.js
index 8641a6fdae6..062577af385 100644
--- a/app/assets/javascripts/blob/balsamiq_viewer.js
+++ b/app/assets/javascripts/blob/balsamiq_viewer.js
@@ -1,9 +1,8 @@
-/* global Flash */
-
+import Flash from '../flash';
 import BalsamiqViewer from './balsamiq/balsamiq_viewer';
 
 function onError() {
-  const flash = new window.Flash('Balsamiq file could not be loaded.');
+  const flash = new Flash('Balsamiq file could not be loaded.');
 
   return flash;
 }
diff --git a/app/assets/javascripts/blob/file_template_mediator.js b/app/assets/javascripts/blob/file_template_mediator.js
index a20c6ca7a21..583e5faa506 100644
--- a/app/assets/javascripts/blob/file_template_mediator.js
+++ b/app/assets/javascripts/blob/file_template_mediator.js
@@ -1,6 +1,5 @@
 /* eslint-disable class-methods-use-this */
-/* global Flash */
-
+import Flash from '../flash';
 import FileTemplateTypeSelector from './template_selectors/type_selector';
 import BlobCiYamlSelector from './template_selectors/ci_yaml_selector';
 import DockerfileSelector from './template_selectors/dockerfile_selector';
diff --git a/app/assets/javascripts/blob/viewer/index.js b/app/assets/javascripts/blob/viewer/index.js
index e0b73f13d36..54132e8537b 100644
--- a/app/assets/javascripts/blob/viewer/index.js
+++ b/app/assets/javascripts/blob/viewer/index.js
@@ -1,4 +1,4 @@
-/* global Flash */
+import Flash from '../../flash';
 import { handleLocationHash } from '../../lib/utils/common_utils';
 
 export default class BlobViewer {
diff --git a/app/assets/javascripts/boards/boards_bundle.js b/app/assets/javascripts/boards/boards_bundle.js
index 815248f38ee..ef4093b59e3 100644
--- a/app/assets/javascripts/boards/boards_bundle.js
+++ b/app/assets/javascripts/boards/boards_bundle.js
@@ -1,10 +1,10 @@
 /* eslint-disable one-var, quote-props, comma-dangle, space-before-function-paren */
 /* global BoardService */
-/* global Flash */
 
 import _ from 'underscore';
 import Vue from 'vue';
 import VueResource from 'vue-resource';
+import Flash from '../flash';
 import FilteredSearchBoards from './filtered_search_boards';
 import eventHub from './eventhub';
 import './models/issue';
diff --git a/app/assets/javascripts/boards/components/board_sidebar.js b/app/assets/javascripts/boards/components/board_sidebar.js
index 590b7be36e3..7f3afefc9cc 100644
--- a/app/assets/javascripts/boards/components/board_sidebar.js
+++ b/app/assets/javascripts/boards/components/board_sidebar.js
@@ -3,9 +3,9 @@
 /* global MilestoneSelect */
 /* global LabelsSelect */
 /* global Sidebar */
-/* global Flash */
 
 import Vue from 'vue';
+import Flash from '../../flash';
 import eventHub from '../../sidebar/event_hub';
 import AssigneeTitle from '../../sidebar/components/assignees/assignee_title';
 import Assignees from '../../sidebar/components/assignees/assignees';
diff --git a/app/assets/javascripts/boards/components/modal/footer.js b/app/assets/javascripts/boards/components/modal/footer.js
index a656f0546c0..de9e44cef35 100644
--- a/app/assets/javascripts/boards/components/modal/footer.js
+++ b/app/assets/javascripts/boards/components/modal/footer.js
@@ -1,7 +1,7 @@
 /* eslint-disable no-new */
-/* global Flash */
 
 import Vue from 'vue';
+import Flash from '../../../flash';
 import './lists_dropdown';
 
 const ModalStore = gl.issueBoards.ModalStore;
diff --git a/app/assets/javascripts/boards/components/sidebar/remove_issue.js b/app/assets/javascripts/boards/components/sidebar/remove_issue.js
index 1e623cf58b7..1ad97211934 100644
--- a/app/assets/javascripts/boards/components/sidebar/remove_issue.js
+++ b/app/assets/javascripts/boards/components/sidebar/remove_issue.js
@@ -1,7 +1,7 @@
 /* eslint-disable no-new */
-/* global Flash */
 
 import Vue from 'vue';
+import Flash from '../../../flash';
 
 const Store = gl.issueBoards.BoardsStore;
 
diff --git a/app/assets/javascripts/create_merge_request_dropdown.js b/app/assets/javascripts/create_merge_request_dropdown.js
index ff2f2c81971..bf40eb3ee11 100644
--- a/app/assets/javascripts/create_merge_request_dropdown.js
+++ b/app/assets/javascripts/create_merge_request_dropdown.js
@@ -1,5 +1,5 @@
 /* eslint-disable no-new */
-/* global Flash */
+import Flash from './flash';
 import DropLab from './droplab/drop_lab';
 import ISetter from './droplab/plugins/input_setter';
 
diff --git a/app/assets/javascripts/cycle_analytics/cycle_analytics_bundle.js b/app/assets/javascripts/cycle_analytics/cycle_analytics_bundle.js
index cdf5e3c0290..49bb6c52180 100644
--- a/app/assets/javascripts/cycle_analytics/cycle_analytics_bundle.js
+++ b/app/assets/javascripts/cycle_analytics/cycle_analytics_bundle.js
@@ -1,7 +1,6 @@
-/* global Flash */
-
 import Vue from 'vue';
 import Cookies from 'js-cookie';
+import Flash from '../flash';
 import Translate from '../vue_shared/translate';
 import banner from './components/banner.vue';
 import stageCodeComponent from './components/stage_code_component.vue';
diff --git a/app/assets/javascripts/deploy_keys/components/app.vue b/app/assets/javascripts/deploy_keys/components/app.vue
index a663e30dfd0..54e13b79a4f 100644
--- a/app/assets/javascripts/deploy_keys/components/app.vue
+++ b/app/assets/javascripts/deploy_keys/components/app.vue
@@ -1,5 +1,5 @@
 <script>
-  /* global Flash */
+  import Flash from '../../flash';
   import eventHub from '../eventhub';
   import DeployKeysService from '../service';
   import DeployKeysStore from '../store';
diff --git a/app/assets/javascripts/diff_notes/components/resolve_btn.js b/app/assets/javascripts/diff_notes/components/resolve_btn.js
index efb6ced9f46..20ddcbfb8bd 100644
--- a/app/assets/javascripts/diff_notes/components/resolve_btn.js
+++ b/app/assets/javascripts/diff_notes/components/resolve_btn.js
@@ -1,9 +1,9 @@
 /* eslint-disable comma-dangle, object-shorthand, func-names, quote-props, no-else-return, camelcase, max-len */
 /* global CommentsStore */
 /* global ResolveService */
-/* global Flash */
 
 import Vue from 'vue';
+import Flash from '../../flash';
 
 const ResolveBtn = Vue.extend({
   props: {
diff --git a/app/assets/javascripts/diff_notes/services/resolve.js b/app/assets/javascripts/diff_notes/services/resolve.js
index 2f063f6fe1f..6eae54f830b 100644
--- a/app/assets/javascripts/diff_notes/services/resolve.js
+++ b/app/assets/javascripts/diff_notes/services/resolve.js
@@ -1,7 +1,7 @@
-/* global Flash */
 /* global CommentsStore */
 
 import Vue from 'vue';
+import Flash from '../../flash';
 import '../../vue_shared/vue_resource_interceptor';
 
 window.gl = window.gl || {};
diff --git a/app/assets/javascripts/environments/components/environment.vue b/app/assets/javascripts/environments/components/environment.vue
index ce5f6219a3e..c039ae85cfb 100644
--- a/app/assets/javascripts/environments/components/environment.vue
+++ b/app/assets/javascripts/environments/components/environment.vue
@@ -1,6 +1,6 @@
 <script>
-/* global Flash */
 import Visibility from 'visibilityjs';
+import Flash from '../../flash';
 import EnvironmentsService from '../services/environments_service';
 import environmentTable from './environments_table.vue';
 import EnvironmentsStore from '../stores/environments_store';
diff --git a/app/assets/javascripts/environments/folder/environments_folder_view.vue b/app/assets/javascripts/environments/folder/environments_folder_view.vue
index 01e70c0bbb7..b155560df9d 100644
--- a/app/assets/javascripts/environments/folder/environments_folder_view.vue
+++ b/app/assets/javascripts/environments/folder/environments_folder_view.vue
@@ -1,6 +1,6 @@
 <script>
-/* global Flash */
 import Visibility from 'visibilityjs';
+import Flash from '../../flash';
 import EnvironmentsService from '../services/environments_service';
 import environmentTable from '../components/environments_table.vue';
 import EnvironmentsStore from '../stores/environments_store';
diff --git a/app/assets/javascripts/filtered_search/dropdown_emoji.js b/app/assets/javascripts/filtered_search/dropdown_emoji.js
index ada14d2053c..a6cc079d720 100644
--- a/app/assets/javascripts/filtered_search/dropdown_emoji.js
+++ b/app/assets/javascripts/filtered_search/dropdown_emoji.js
@@ -1,7 +1,6 @@
-/* global Flash */
-
-import Ajax from '~/droplab/plugins/ajax';
-import Filter from '~/droplab/plugins/filter';
+import Flash from '../flash';
+import Ajax from '../droplab/plugins/ajax';
+import Filter from '../droplab/plugins/filter';
 import './filtered_search_dropdown';
 
 class DropdownEmoji extends gl.FilteredSearchDropdown {
diff --git a/app/assets/javascripts/filtered_search/dropdown_non_user.js b/app/assets/javascripts/filtered_search/dropdown_non_user.js
index b32d589481d..788fb1dc614 100644
--- a/app/assets/javascripts/filtered_search/dropdown_non_user.js
+++ b/app/assets/javascripts/filtered_search/dropdown_non_user.js
@@ -1,7 +1,6 @@
-/* global Flash */
-
-import Ajax from '~/droplab/plugins/ajax';
-import Filter from '~/droplab/plugins/filter';
+import Flash from '../flash';
+import Ajax from '../droplab/plugins/ajax';
+import Filter from '../droplab/plugins/filter';
 import './filtered_search_dropdown';
 
 class DropdownNonUser extends gl.FilteredSearchDropdown {
diff --git a/app/assets/javascripts/filtered_search/dropdown_user.js b/app/assets/javascripts/filtered_search/dropdown_user.js
index ce8817b1b2e..a9e2b65def0 100644
--- a/app/assets/javascripts/filtered_search/dropdown_user.js
+++ b/app/assets/javascripts/filtered_search/dropdown_user.js
@@ -1,6 +1,5 @@
-/* global Flash */
-
-import AjaxFilter from '~/droplab/plugins/ajax_filter';
+import Flash from '../flash';
+import AjaxFilter from '../droplab/plugins/ajax_filter';
 import './filtered_search_dropdown';
 import { addClassIfElementExists } from '../lib/utils/dom_utils';
 
diff --git a/app/assets/javascripts/filtered_search/filtered_search_manager.js b/app/assets/javascripts/filtered_search/filtered_search_manager.js
index a44dc279a6f..7b233842d5a 100644
--- a/app/assets/javascripts/filtered_search/filtered_search_manager.js
+++ b/app/assets/javascripts/filtered_search/filtered_search_manager.js
@@ -1,3 +1,4 @@
+import Flash from '../flash';
 import FilteredSearchContainer from './container';
 import RecentSearchesRoot from './recent_searches_root';
 import RecentSearchesStore from './stores/recent_searches_store';
@@ -36,7 +37,7 @@ class FilteredSearchManager {
       .catch((error) => {
         if (error.name === 'RecentSearchesServiceError') return undefined;
         // eslint-disable-next-line no-new
-        new window.Flash('An error occurred while parsing recent searches');
+        new Flash('An error occurred while parsing recent searches');
         // Gracefully fail to empty array
         return [];
       })
diff --git a/app/assets/javascripts/filtered_search/filtered_search_visual_tokens.js b/app/assets/javascripts/filtered_search/filtered_search_visual_tokens.js
index 28e8240169d..dd24fc44d2a 100644
--- a/app/assets/javascripts/filtered_search/filtered_search_visual_tokens.js
+++ b/app/assets/javascripts/filtered_search/filtered_search_visual_tokens.js
@@ -1,5 +1,5 @@
 import AjaxCache from '../lib/utils/ajax_cache';
-import '../flash'; /* global Flash */
+import Flash from '../flash';
 import FilteredSearchContainer from './container';
 import UsersCache from '../lib/utils/users_cache';
 
diff --git a/app/assets/javascripts/flash.js b/app/assets/javascripts/flash.js
index ccff8f0ace7..bc5cd818e1c 100644
--- a/app/assets/javascripts/flash.js
+++ b/app/assets/javascripts/flash.js
@@ -1,71 +1,94 @@
-/* eslint-disable func-names, space-before-function-paren, wrap-iife, no-var, one-var, one-var-declaration-per-line, no-param-reassign, quotes, quote-props, prefer-template, comma-dangle, max-len */
+import _ from 'underscore';
 
-window.Flash = (function() {
-  var hideFlash;
+const hideFlash = (flashEl, fadeTransition = true) => {
+  if (fadeTransition) {
+    Object.assign(flashEl.style, {
+      transition: 'opacity .3s',
+      opacity: '0',
+    });
+  }
 
-  hideFlash = function() {
-    return $(this).fadeOut();
-  };
+  flashEl.addEventListener('transitionend', () => {
+    flashEl.remove();
+  }, {
+    once: true,
+    passive: true,
+  });
 
-  /**
-   * Flash banner supports different types of Flash configurations
-   * along with ability to provide actionConfig which can be used to show
-   * additional action or link on banner next to message
-   *
-   * @param {String} message Flash message
-   * @param {String} type Type of Flash, it can be `notice` or `alert` (default)
-   * @param {Object} parent Reference to Parent element under which Flash needs to appear
-   * @param {Object} actionConfig Map of config to show action on banner
-   *    @param {String} href URL to which action link should point (default '#')
-   *    @param {String} title Title of action
-   *    @param {Function} clickHandler Method to call when action is clicked on
-   */
-  function Flash(message, type, parent, actionConfig) {
-    var flash, textDiv, actionLink;
-    if (type == null) {
-      type = 'alert';
-    }
-    if (parent == null) {
-      parent = null;
-    }
-    if (parent) {
-      this.flashContainer = parent.find('.flash-container');
-    } else {
-      this.flashContainer = $('.flash-container-page');
-    }
-    this.flashContainer.html('');
-    flash = $('<div/>', {
-      "class": "flash-" + type
-    });
-    flash.on('click', hideFlash);
-    textDiv = $('<div/>', {
-      "class": 'flash-text',
-      text: message
-    });
-    textDiv.appendTo(flash);
+  if (!fadeTransition) flashEl.dispatchEvent(new Event('transitionend'));
+};
 
-    if (actionConfig) {
-      const actionLinkConfig = {
-        class: 'flash-action',
-        href: actionConfig.href || '#',
-        text: actionConfig.title
-      };
+const createAction = config => `
+  <a
+    href="${config.href || '#'}"
+    class="flash-action"
+    ${config.href ? '' : 'role="button"'}
+  >
+    ${_.escape(config.title)}
+  </a>
+`;
 
-      if (!actionConfig.href) {
-        actionLinkConfig.role = 'button';
-      }
+const createFlashEl = (message, type, isInContentWrapper = false) => `
+  <div
+    class="flash-${type}"
+  >
+    <div
+      class="flash-text ${isInContentWrapper ? 'container-fluid container-limited' : ''}"
+    >
+      ${_.escape(message)}
+    </div>
+  </div>
+`;
 
-      actionLink = $('<a/>', actionLinkConfig);
+/*
+ *  Flash banner supports different types of Flash configurations
+ *  along with ability to provide actionConfig which can be used to show
+ *  additional action or link on banner next to message
+ *
+ *  @param {String} message           Flash message text
+ *  @param {String} type              Type of Flash, it can be `notice` or `alert` (default)
+ *  @param {Object} parent            Reference to parent element under which Flash needs to appear
+ *  @param {Object} actonConfig       Map of config to show action on banner
+ *    @param {String} href            URL to which action config should point to (default: '#')
+ *    @param {String} title           Title of action
+ *    @param {Function} clickHandler  Method to call when action is clicked on
+ *  @param {Boolean} fadeTransition   Boolean to determine whether to fade the alert out
+ */
+const createFlash = function createFlash(
+  message,
+  type = 'alert',
+  parent = document,
+  actionConfig = null,
+  fadeTransition = true,
+) {
+  const flashContainer = parent.querySelector('.flash-container');
 
-      actionLink.appendTo(flash);
-      this.flashContainer.on('click', '.flash-action', actionConfig.clickHandler);
-    }
-    if (this.flashContainer.parent().hasClass('content-wrapper')) {
-      textDiv.addClass('container-fluid container-limited');
+  if (!flashContainer) return null;
+
+  const isInContentWrapper = flashContainer.parentNode.classList.contains('content-wrapper');
+
+  flashContainer.innerHTML = createFlashEl(message, type, isInContentWrapper);
+
+  const flashEl = flashContainer.querySelector(`.flash-${type}`);
+  flashEl.addEventListener('click', () => hideFlash(flashEl, fadeTransition));
+
+  if (actionConfig) {
+    flashEl.innerHTML += createAction(actionConfig);
+
+    if (actionConfig.clickHandler) {
+      flashEl.querySelector('.flash-action').addEventListener('click', e => actionConfig.clickHandler(e));
     }
-    flash.appendTo(this.flashContainer);
-    this.flashContainer.show();
   }
 
-  return Flash;
-})();
+  flashContainer.style.display = 'block';
+
+  return flashContainer;
+};
+
+export {
+  createFlash as default,
+  createFlashEl,
+  createAction,
+  hideFlash,
+};
+window.Flash = createFlash;
diff --git a/app/assets/javascripts/groups/index.js b/app/assets/javascripts/groups/index.js
index 9ad8e5c6052..600bae24b52 100644
--- a/app/assets/javascripts/groups/index.js
+++ b/app/assets/javascripts/groups/index.js
@@ -1,6 +1,5 @@
-/* global Flash */
-
 import Vue from 'vue';
+import Flash from '../flash';
 import GroupFilterableList from './groups_filterable_list';
 import GroupsComponent from './components/groups.vue';
 import GroupFolder from './components/group_folder.vue';
diff --git a/app/assets/javascripts/integrations/integration_settings_form.js b/app/assets/javascripts/integrations/integration_settings_form.js
index cf1e6a14725..32415a8791f 100644
--- a/app/assets/javascripts/integrations/integration_settings_form.js
+++ b/app/assets/javascripts/integrations/integration_settings_form.js
@@ -1,4 +1,4 @@
-/* global Flash */
+import Flash from '../flash';
 
 export default class IntegrationSettingsForm {
   constructor(formSelector) {
@@ -102,7 +102,7 @@ export default class IntegrationSettingsForm {
     })
     .done((res) => {
       if (res.error) {
-        new Flash(`${res.message} ${res.service_response}`, null, null, {
+        new Flash(`${res.message} ${res.service_response}`, 'alert', document, {
           title: 'Save anyway',
           clickHandler: (e) => {
             e.preventDefault();
diff --git a/app/assets/javascripts/issuable_bulk_update_actions.js b/app/assets/javascripts/issuable_bulk_update_actions.js
index c39ffdb2e0f..eb15949603f 100644
--- a/app/assets/javascripts/issuable_bulk_update_actions.js
+++ b/app/assets/javascripts/issuable_bulk_update_actions.js
@@ -1,7 +1,7 @@
 /* eslint-disable comma-dangle, quotes, consistent-return, func-names, array-callback-return, space-before-function-paren, prefer-arrow-callback, max-len, no-unused-expressions, no-sequences, no-underscore-dangle, no-unused-vars, no-param-reassign */
 /* global IssuableIndex */
-/* global Flash */
 import _ from 'underscore';
+import Flash from './flash';
 
 export default {
   init({ container, form, issues, prefixId } = {}) {
diff --git a/app/assets/javascripts/issue.js b/app/assets/javascripts/issue.js
index c0bd64814ca..3fc29f9a661 100644
--- a/app/assets/javascripts/issue.js
+++ b/app/assets/javascripts/issue.js
@@ -1,9 +1,7 @@
 /* eslint-disable func-names, space-before-function-paren, no-var, prefer-rest-params, wrap-iife, one-var, no-underscore-dangle, one-var-declaration-per-line, object-shorthand, no-unused-vars, no-new, comma-dangle, consistent-return, quotes, dot-notation, quote-props, prefer-arrow-callback, max-len */
-/* global Flash */
-
 import 'vendor/jquery.waitforimages';
 import '~/lib/utils/text_utility';
-import './flash';
+import Flash from './flash';
 import TaskList from './task_list';
 import CreateMergeRequestDropdown from './create_merge_request_dropdown';
 import IssuablesHelper from './helpers/issuables_helper';
diff --git a/app/assets/javascripts/issue_show/components/app.vue b/app/assets/javascripts/issue_show/components/app.vue
index 06f6ec241f4..eecb56cb185 100644
--- a/app/assets/javascripts/issue_show/components/app.vue
+++ b/app/assets/javascripts/issue_show/components/app.vue
@@ -1,5 +1,4 @@
 <script>
-/* global Flash */
 import Visibility from 'visibilityjs';
 import Poll from '../../lib/utils/poll';
 import eventHub from '../event_hub';
@@ -153,7 +152,7 @@ export default {
         })
         .catch(() => {
           eventHub.$emit('close.form');
-          return new Flash('Error updating issue');
+          window.Flash('Error updating issue');
         });
     },
     deleteIssuable() {
@@ -167,7 +166,7 @@ export default {
         })
         .catch(() => {
           eventHub.$emit('close.form');
-          return new Flash('Error deleting issue');
+          window.Flash('Error deleting issue');
         });
     },
   },
diff --git a/app/assets/javascripts/issue_show/components/fields/description.vue b/app/assets/javascripts/issue_show/components/fields/description.vue
index dc902eefc5f..0aa1b2c2e31 100644
--- a/app/assets/javascripts/issue_show/components/fields/description.vue
+++ b/app/assets/javascripts/issue_show/components/fields/description.vue
@@ -1,5 +1,4 @@
 <script>
-  /* global Flash */
   import updateMixin from '../../mixins/update';
   import markdownField from '../../../vue_shared/components/markdown/field.vue';
 
diff --git a/app/assets/javascripts/jobs/job_details_bundle.js b/app/assets/javascripts/jobs/job_details_bundle.js
index f92e669414a..baaf5641200 100644
--- a/app/assets/javascripts/jobs/job_details_bundle.js
+++ b/app/assets/javascripts/jobs/job_details_bundle.js
@@ -1,5 +1,3 @@
-/* global Flash */
-
 import Vue from 'vue';
 import JobMediator from './job_details_mediator';
 import jobHeader from './components/header.vue';
diff --git a/app/assets/javascripts/jobs/job_details_mediator.js b/app/assets/javascripts/jobs/job_details_mediator.js
index 14c7b96e54d..3e2658f9fc1 100644
--- a/app/assets/javascripts/jobs/job_details_mediator.js
+++ b/app/assets/javascripts/jobs/job_details_mediator.js
@@ -1,7 +1,7 @@
-/* global Flash */
 /* global Build */
 
 import Visibility from 'visibilityjs';
+import Flash from '../flash';
 import Poll from '../lib/utils/poll';
 import JobStore from './stores/job_store';
 import JobService from './services/job_service';
diff --git a/app/assets/javascripts/label_manager.js b/app/assets/javascripts/label_manager.js
index d8814802d9e..a8f613c6cf2 100644
--- a/app/assets/javascripts/label_manager.js
+++ b/app/assets/javascripts/label_manager.js
@@ -1,7 +1,8 @@
 /* eslint-disable comma-dangle, class-methods-use-this, no-underscore-dangle, no-param-reassign, no-unused-vars, consistent-return, func-names, space-before-function-paren, max-len */
-/* global Flash */
 /* global Sortable */
 
+import Flash from './flash';
+
 ((global) => {
   class LabelManager {
     constructor({ togglePriorityButton, prioritizedLabels, otherLabels } = {}) {
diff --git a/app/assets/javascripts/main.js b/app/assets/javascripts/main.js
index ac7b976f811..abb238abbc3 100644
--- a/app/assets/javascripts/main.js
+++ b/app/assets/javascripts/main.js
@@ -1,5 +1,4 @@
 /* eslint-disable func-names, space-before-function-paren, no-var, quotes, consistent-return, prefer-arrow-callback, comma-dangle, object-shorthand, no-new, max-len, no-multi-spaces, import/newline-after-import, import/first */
-/* global Flash */
 /* global ConfirmDangerModal */
 /* global Aside */
 
@@ -71,7 +70,7 @@ import './diff';
 import './dropzone_input';
 import './due_date_select';
 import './files_comment_button';
-import './flash';
+import Flash from './flash';
 import './gl_dropdown';
 import './gl_field_error';
 import './gl_field_errors';
@@ -164,7 +163,6 @@ $(function () {
   var $document = $(document);
   var $window = $(window);
   var $sidebarGutterToggle = $('.js-sidebar-toggle');
-  var $flash = $('.flash-container');
   var bootstrapBreakpoint = bp.getBreakpointSize();
   var fitSidebarForSize;
 
@@ -249,13 +247,6 @@ $(function () {
   // Form submitter
   });
   gl.utils.localTimeAgo($('abbr.timeago, .js-timeago'), true);
-  // Flash
-  if ($flash.length > 0) {
-    $flash.click(function () {
-      return $(this).fadeOut();
-    });
-    $flash.show();
-  }
   // Disable form buttons while a form is submitting
   $body.on('ajax:complete, ajax:beforeSend, submit', 'form', function (e) {
     var buttons;
diff --git a/app/assets/javascripts/merge_conflicts/components/diff_file_editor.js b/app/assets/javascripts/merge_conflicts/components/diff_file_editor.js
index 645045fea88..93f8f6ee926 100644
--- a/app/assets/javascripts/merge_conflicts/components/diff_file_editor.js
+++ b/app/assets/javascripts/merge_conflicts/components/diff_file_editor.js
@@ -1,8 +1,8 @@
 /* eslint-disable comma-dangle, quote-props, no-useless-computed-key, object-shorthand, no-new, no-param-reassign, max-len */
 /* global ace */
-/* global Flash */
 
 import Vue from 'vue';
+import Flash from '../../flash';
 
 ((global) => {
   global.mergeConflicts = global.mergeConflicts || {};
diff --git a/app/assets/javascripts/merge_conflicts/merge_conflicts_bundle.js b/app/assets/javascripts/merge_conflicts/merge_conflicts_bundle.js
index d74cf5328ad..17591829b76 100644
--- a/app/assets/javascripts/merge_conflicts/merge_conflicts_bundle.js
+++ b/app/assets/javascripts/merge_conflicts/merge_conflicts_bundle.js
@@ -1,7 +1,7 @@
 /* eslint-disable new-cap, comma-dangle, no-new */
-/* global Flash */
 
 import Vue from 'vue';
+import Flash from '../flash';
 import initIssuableSidebar from '../init_issuable_sidebar';
 import './merge_conflict_store';
 import './merge_conflict_service';
diff --git a/app/assets/javascripts/merge_request_tabs.js b/app/assets/javascripts/merge_request_tabs.js
index c042b22d1fd..df042c7baff 100644
--- a/app/assets/javascripts/merge_request_tabs.js
+++ b/app/assets/javascripts/merge_request_tabs.js
@@ -1,9 +1,8 @@
 /* eslint-disable no-new, class-methods-use-this */
-/* global Flash */
 /* global notes */
 
 import Cookies from 'js-cookie';
-import './flash';
+import Flash from './flash';
 import BlobForkSuggestion from './blob/blob_fork_suggestion';
 import initChangesDropdown from './init_changes_dropdown';
 import bp from './breakpoints';
diff --git a/app/assets/javascripts/milestone.js b/app/assets/javascripts/milestone.js
index 3e07ec4d0aa..8f3f1986763 100644
--- a/app/assets/javascripts/milestone.js
+++ b/app/assets/javascripts/milestone.js
@@ -1,7 +1,8 @@
 /* eslint-disable func-names, space-before-function-paren, wrap-iife, no-use-before-define, camelcase, quotes, object-shorthand, no-shadow, no-unused-vars, comma-dangle, no-var, prefer-template, no-underscore-dangle, consistent-return, one-var, one-var-declaration-per-line, default-case, prefer-arrow-callback, max-len */
-/* global Flash */
 /* global Sortable */
 
+import Flash from './flash';
+
 (function() {
   this.Milestone = (function() {
     function Milestone() {
diff --git a/app/assets/javascripts/mini_pipeline_graph_dropdown.js b/app/assets/javascripts/mini_pipeline_graph_dropdown.js
index 64c1447f427..ca3d271663b 100644
--- a/app/assets/javascripts/mini_pipeline_graph_dropdown.js
+++ b/app/assets/javascripts/mini_pipeline_graph_dropdown.js
@@ -1,5 +1,5 @@
 /* eslint-disable no-new */
-/* global Flash */
+import Flash from './flash';
 
 /**
  * In each pipelines table we have a mini pipeline graph for each pipeline.
diff --git a/app/assets/javascripts/monitoring/components/dashboard.vue b/app/assets/javascripts/monitoring/components/dashboard.vue
index 442ed86d50c..cbe24c0915b 100644
--- a/app/assets/javascripts/monitoring/components/dashboard.vue
+++ b/app/assets/javascripts/monitoring/components/dashboard.vue
@@ -1,6 +1,6 @@
 <script>
-  /* global Flash */
   import _ from 'underscore';
+  import Flash from '../../flash';
   import MonitoringService from '../services/monitoring_service';
   import GraphGroup from './graph_group.vue';
   import Graph from './graph.vue';
diff --git a/app/assets/javascripts/notes.js b/app/assets/javascripts/notes.js
index 24de21f2ce2..cf7322ba1da 100644
--- a/app/assets/javascripts/notes.js
+++ b/app/assets/javascripts/notes.js
@@ -5,7 +5,6 @@ default-case, prefer-template, consistent-return, no-alert, no-return-assign,
 no-param-reassign, prefer-arrow-callback, no-else-return, comma-dangle, no-new,
 brace-style, no-lonely-if, vars-on-top, no-unused-vars, no-sequences, no-shadow,
 newline-per-chained-call, no-useless-escape, class-methods-use-this */
-/* global Flash */
 /* global Autosave */
 /* global ResolveService */
 /* global mrRefreshWidgetUrl */
@@ -18,6 +17,7 @@ import Dropzone from 'dropzone';
 import 'vendor/jquery.caret'; // required by jquery.atwho
 import 'vendor/jquery.atwho';
 import AjaxCache from '~/lib/utils/ajax_cache';
+import Flash from './flash';
 import CommentTypeToggle from './comment_type_toggle';
 import loadAwardsHandler from './awards_handler';
 import './autosave';
@@ -354,7 +354,7 @@ export default class Notes {
             Object.keys(noteEntity.commands_changes).length > 0) {
           $notesList.find('.system-note.being-posted').remove();
         }
-        this.addFlash(noteEntity.errors.commands_only, 'notice', this.parentTimeline);
+        this.addFlash(noteEntity.errors.commands_only, 'notice', this.parentTimeline.get(0));
         this.refresh();
       }
       return;
@@ -593,7 +593,7 @@ export default class Notes {
     } else if ($form.hasClass('js-discussion-note-form')) {
       formParentTimeline = $form.closest('.discussion-notes').find('.notes');
     }
-    return this.addFlash('Your comment could not be submitted! Please check your network connection and try again.', 'alert', formParentTimeline);
+    return this.addFlash('Your comment could not be submitted! Please check your network connection and try again.', 'alert', formParentTimeline.get(0));
   }
 
   updateNoteError($parentTimeline) {
@@ -1213,13 +1213,13 @@ export default class Notes {
   }
 
   addFlash(...flashParams) {
-    this.flashInstance = new Flash(...flashParams);
+    this.flashContainer = new Flash(...flashParams);
   }
 
   clearFlash() {
-    if (this.flashInstance && this.flashInstance.flashContainer) {
-      this.flashInstance.flashContainer.hide();
-      this.flashInstance = null;
+    if (this.flashContainer) {
+      this.flashContainer.style.display = 'none';
+      this.flashContainer = null;
     }
   }
 
diff --git a/app/assets/javascripts/notes/components/issue_comment_form.vue b/app/assets/javascripts/notes/components/issue_comment_form.vue
index ab8516296a8..2ce52e4538a 100644
--- a/app/assets/javascripts/notes/components/issue_comment_form.vue
+++ b/app/assets/javascripts/notes/components/issue_comment_form.vue
@@ -1,8 +1,9 @@
 <script>
-  /* global Flash, Autosave */
+  /* global Autosave */
   import { mapActions, mapGetters } from 'vuex';
   import _ from 'underscore';
   import autosize from 'vendor/autosize';
+  import Flash from '../../flash';
   import '../../autosave';
   import TaskList from '../../task_list';
   import * as constants from '../constants';
@@ -145,7 +146,7 @@
                   Flash(
                     'Something went wrong while adding your comment. Please try again.',
                     'alert',
-                    $(this.$refs.commentForm),
+                    this.$refs.commentForm,
                   );
                 }
               } else {
@@ -160,7 +161,7 @@
               this.isSubmitting = false;
               this.discard(false);
               const msg = 'Your comment could not be submitted! Please check your network connection and try again.';
-              Flash(msg, 'alert', $(this.$el));
+              Flash(msg, 'alert', this.$el);
               this.note = noteData.data.note.note; // Restore textarea content.
               this.removePlaceholderNotes();
             });
diff --git a/app/assets/javascripts/notes/components/issue_discussion.vue b/app/assets/javascripts/notes/components/issue_discussion.vue
index b131ef4b182..baf43190d9e 100644
--- a/app/assets/javascripts/notes/components/issue_discussion.vue
+++ b/app/assets/javascripts/notes/components/issue_discussion.vue
@@ -1,6 +1,6 @@
 <script>
-  /* global Flash */
   import { mapActions, mapGetters } from 'vuex';
+  import Flash from '../../flash';
   import { SYSTEM_NOTE } from '../constants';
   import issueNote from './issue_note.vue';
   import userAvatarLink from '../../vue_shared/components/user_avatar/user_avatar_link.vue';
@@ -133,7 +133,7 @@
             this.isReplying = true;
             this.$nextTick(() => {
               const msg = 'Your comment could not be submitted! Please check your network connection and try again.';
-              Flash(msg, 'alert', $(this.$el));
+              Flash(msg, 'alert', this.$el);
               this.$refs.noteForm.note = noteText;
               callback(err);
             });
diff --git a/app/assets/javascripts/notes/components/issue_note.vue b/app/assets/javascripts/notes/components/issue_note.vue
index 1f43b8a16ad..0ddbd672bed 100644
--- a/app/assets/javascripts/notes/components/issue_note.vue
+++ b/app/assets/javascripts/notes/components/issue_note.vue
@@ -1,7 +1,6 @@
 <script>
-  /* global Flash */
-
   import { mapGetters, mapActions } from 'vuex';
+  import Flash from '../../flash';
   import userAvatarLink from '../../vue_shared/components/user_avatar/user_avatar_link.vue';
   import issueNoteHeader from './issue_note_header.vue';
   import issueNoteActions from './issue_note_actions.vue';
@@ -101,7 +100,7 @@
             this.isEditing = true;
             this.$nextTick(() => {
               const msg = 'Something went wrong while editing your comment. Please try again.';
-              Flash(msg, 'alert', $(this.$el));
+              Flash(msg, 'alert', this.$el);
               this.recoverNoteContent(noteText);
               callback();
             });
diff --git a/app/assets/javascripts/notes/components/issue_note_awards_list.vue b/app/assets/javascripts/notes/components/issue_note_awards_list.vue
index d42e61e3899..c3a340139e7 100644
--- a/app/assets/javascripts/notes/components/issue_note_awards_list.vue
+++ b/app/assets/javascripts/notes/components/issue_note_awards_list.vue
@@ -1,10 +1,9 @@
 <script>
-  /* global Flash */
-
   import { mapActions, mapGetters } from 'vuex';
   import emojiSmiling from 'icons/_emoji_slightly_smiling_face.svg';
   import emojiSmile from 'icons/_emoji_smile.svg';
   import emojiSmiley from 'icons/_emoji_smiley.svg';
+  import Flash from '../../flash';
   import { glEmojiTag } from '../../emoji';
   import tooltip from '../../vue_shared/directives/tooltip';
 
diff --git a/app/assets/javascripts/notes/components/issue_notes_app.vue b/app/assets/javascripts/notes/components/issue_notes_app.vue
index b6fc5e5036f..aecd1f957e5 100644
--- a/app/assets/javascripts/notes/components/issue_notes_app.vue
+++ b/app/assets/javascripts/notes/components/issue_notes_app.vue
@@ -1,6 +1,6 @@
 <script>
-  /* global Flash */
   import { mapGetters, mapActions } from 'vuex';
+  import Flash from '../../flash';
   import store from '../stores/';
   import * as constants from '../constants';
   import issueNote from './issue_note.vue';
diff --git a/app/assets/javascripts/notes/stores/actions.js b/app/assets/javascripts/notes/stores/actions.js
index 1a791039909..6f04aecc9b7 100644
--- a/app/assets/javascripts/notes/stores/actions.js
+++ b/app/assets/javascripts/notes/stores/actions.js
@@ -1,5 +1,5 @@
-/* global Flash */
 import Visibility from 'visibilityjs';
+import Flash from '../../flash';
 import Poll from '../../lib/utils/poll';
 import * as types from './mutation_types';
 import * as utils from './utils';
@@ -99,7 +99,7 @@ export const saveNote = ({ commit, dispatch }, noteData) => {
         eTagPoll.makeRequest();
 
         $('.js-gfm-input').trigger('clear-commands-cache.atwho');
-        Flash('Commands applied', 'notice', $(noteData.flashContainer));
+        Flash('Commands applied', 'notice', noteData.flashContainer);
       }
 
       if (commandsChanges) {
@@ -114,8 +114,8 @@ export const saveNote = ({ commit, dispatch }, noteData) => {
             .catch(() => {
               Flash(
                 'Something went wrong while adding your award. Please try again.',
-                null,
-                $(noteData.flashContainer),
+                'alert',
+                noteData.flashContainer,
               );
             });
         }
@@ -126,7 +126,7 @@ export const saveNote = ({ commit, dispatch }, noteData) => {
       }
 
       if (errors && errors.commands_only) {
-        Flash(errors.commands_only, 'notice', $(noteData.flashContainer));
+        Flash(errors.commands_only, 'notice', noteData.flashContainer);
       }
       commit(types.REMOVE_PLACEHOLDER_NOTES);
 
diff --git a/app/assets/javascripts/notifications_dropdown.js b/app/assets/javascripts/notifications_dropdown.js
index 838356133cd..f90ac2d9f71 100644
--- a/app/assets/javascripts/notifications_dropdown.js
+++ b/app/assets/javascripts/notifications_dropdown.js
@@ -1,5 +1,5 @@
 /* eslint-disable func-names, space-before-function-paren, wrap-iife, one-var, no-var, one-var-declaration-per-line, no-unused-vars, consistent-return, prefer-arrow-callback, no-else-return, max-len */
-/* global Flash */
+import Flash from './flash';
 
 (function() {
   this.NotificationsDropdown = (function() {
diff --git a/app/assets/javascripts/pipelines/components/pipelines_actions.vue b/app/assets/javascripts/pipelines/components/pipelines_actions.vue
index c4c63a52358..f3c0aca17ba 100644
--- a/app/assets/javascripts/pipelines/components/pipelines_actions.vue
+++ b/app/assets/javascripts/pipelines/components/pipelines_actions.vue
@@ -1,6 +1,4 @@
 <script>
-  /* global Flash */
-  import '~/flash';
   import playIconSvg from 'icons/_icon_play.svg';
   import eventHub from '../event_hub';
   import loadingIcon from '../../vue_shared/components/loading_icon.vue';
diff --git a/app/assets/javascripts/pipelines/components/stage.vue b/app/assets/javascripts/pipelines/components/stage.vue
index a4a27247406..1a7a5c2a415 100644
--- a/app/assets/javascripts/pipelines/components/stage.vue
+++ b/app/assets/javascripts/pipelines/components/stage.vue
@@ -13,7 +13,7 @@
  * 4. Commit widget
  */
 
-/* global Flash */
+import Flash from '../../flash';
 import { borderlessStatusIconEntityMap } from '../../vue_shared/ci_status_icons';
 import loadingIcon from '../../vue_shared/components/loading_icon.vue';
 import tooltip from '../../vue_shared/directives/tooltip';
diff --git a/app/assets/javascripts/pipelines/mixins/pipelines.js b/app/assets/javascripts/pipelines/mixins/pipelines.js
index e97f5632dc8..50bdf80c3e3 100644
--- a/app/assets/javascripts/pipelines/mixins/pipelines.js
+++ b/app/assets/javascripts/pipelines/mixins/pipelines.js
@@ -1,6 +1,5 @@
-/* global Flash */
-import '~/flash';
 import Visibility from 'visibilityjs';
+import Flash from '../../flash';
 import Poll from '../../lib/utils/poll';
 import emptyState from '../components/empty_state.vue';
 import errorState from '../components/error_state.vue';
diff --git a/app/assets/javascripts/pipelines/pipeline_details_bundle.js b/app/assets/javascripts/pipelines/pipeline_details_bundle.js
index bfc416da50b..206023d4ddb 100644
--- a/app/assets/javascripts/pipelines/pipeline_details_bundle.js
+++ b/app/assets/javascripts/pipelines/pipeline_details_bundle.js
@@ -1,6 +1,5 @@
-/* global Flash */
-
 import Vue from 'vue';
+import Flash from '../flash';
 import PipelinesMediator from './pipeline_details_mediatior';
 import pipelineGraph from './components/graph/graph_component.vue';
 import pipelineHeader from './components/header_component.vue';
diff --git a/app/assets/javascripts/pipelines/pipeline_details_mediatior.js b/app/assets/javascripts/pipelines/pipeline_details_mediatior.js
index 385e7430a7d..823ccd849f4 100644
--- a/app/assets/javascripts/pipelines/pipeline_details_mediatior.js
+++ b/app/assets/javascripts/pipelines/pipeline_details_mediatior.js
@@ -1,6 +1,5 @@
-/* global Flash */
-
 import Visibility from 'visibilityjs';
+import Flash from '../flash';
 import Poll from '../lib/utils/poll';
 import PipelineStore from './stores/pipeline_store';
 import PipelineService from './services/pipeline_service';
diff --git a/app/assets/javascripts/profile/profile.js b/app/assets/javascripts/profile/profile.js
index 3deb242bc1f..0dc02f012e4 100644
--- a/app/assets/javascripts/profile/profile.js
+++ b/app/assets/javascripts/profile/profile.js
@@ -1,5 +1,5 @@
 /* eslint-disable comma-dangle, no-unused-vars, class-methods-use-this, quotes, consistent-return, func-names, prefer-arrow-callback, space-before-function-paren, max-len */
-/* global Flash */
+import Flash from '../flash';
 import { getPagePath } from '../lib/utils/common_utils';
 
 ((global) => {
diff --git a/app/assets/javascripts/protected_branches/protected_branch_edit.js b/app/assets/javascripts/protected_branches/protected_branch_edit.js
index 3b920942a3f..632625da8e7 100644
--- a/app/assets/javascripts/protected_branches/protected_branch_edit.js
+++ b/app/assets/javascripts/protected_branches/protected_branch_edit.js
@@ -1,6 +1,5 @@
 /* eslint-disable no-new */
-/* global Flash */
-
+import Flash from '../flash';
 import ProtectedBranchAccessDropdown from './protected_branch_access_dropdown';
 
 export default class ProtectedBranchEdit {
@@ -57,7 +56,7 @@ export default class ProtectedBranchEdit {
         },
       },
       error() {
-        new Flash('Failed to update branch!', null, $('.js-protected-branches-list'));
+        new Flash('Failed to update branch!', 'alert', document.querySelector('.js-protected-branches-list'));
       },
     }).always(() => {
       this.$allowedToMergeDropdown.enable();
diff --git a/app/assets/javascripts/protected_tags/protected_tag_edit.js b/app/assets/javascripts/protected_tags/protected_tag_edit.js
index 09a387c0f9e..dad0ad25b65 100644
--- a/app/assets/javascripts/protected_tags/protected_tag_edit.js
+++ b/app/assets/javascripts/protected_tags/protected_tag_edit.js
@@ -1,6 +1,5 @@
 /* eslint-disable no-new */
-/* global Flash */
-
+import Flash from '../flash';
 import ProtectedTagAccessDropdown from './protected_tag_access_dropdown';
 
 export default class ProtectedTagEdit {
@@ -43,7 +42,7 @@ export default class ProtectedTagEdit {
         },
       },
       error() {
-        new Flash('Failed to update tag!', null, $('.js-protected-tags-list'));
+        new Flash('Failed to update tag!', 'alert', document.querySelector('.js-protected-tags-list'));
       },
     }).always(() => {
       this.$allowedToCreateDropdownButton.enable();
diff --git a/app/assets/javascripts/repo/components/repo_commit_section.vue b/app/assets/javascripts/repo/components/repo_commit_section.vue
index 119e38c583d..6d8cc964eb2 100644
--- a/app/assets/javascripts/repo/components/repo_commit_section.vue
+++ b/app/assets/javascripts/repo/components/repo_commit_section.vue
@@ -1,5 +1,5 @@
 <script>
-/* global Flash */
+import Flash from '../../flash';
 import Store from '../stores/repo_store';
 import RepoMixin from '../mixins/repo_mixin';
 import Service from '../services/repo_service';
diff --git a/app/assets/javascripts/repo/helpers/repo_helper.js b/app/assets/javascripts/repo/helpers/repo_helper.js
index 7483f8bc305..46204598e1d 100644
--- a/app/assets/javascripts/repo/helpers/repo_helper.js
+++ b/app/assets/javascripts/repo/helpers/repo_helper.js
@@ -1,7 +1,6 @@
-/* global Flash */
 import Service from '../services/repo_service';
 import Store from '../stores/repo_store';
-import '../../flash';
+import Flash from '../../flash';
 
 const RepoHelper = {
   monacoInstance: null,
diff --git a/app/assets/javascripts/repo/services/repo_service.js b/app/assets/javascripts/repo/services/repo_service.js
index af83497fa39..830685f7e6e 100644
--- a/app/assets/javascripts/repo/services/repo_service.js
+++ b/app/assets/javascripts/repo/services/repo_service.js
@@ -1,4 +1,3 @@
-/* global Flash */
 import axios from 'axios';
 import Store from '../stores/repo_store';
 import Api from '../../api';
diff --git a/app/assets/javascripts/repo/stores/repo_store.js b/app/assets/javascripts/repo/stores/repo_store.js
index 93b39cff27e..c633f538c1b 100644
--- a/app/assets/javascripts/repo/stores/repo_store.js
+++ b/app/assets/javascripts/repo/stores/repo_store.js
@@ -1,4 +1,3 @@
-/* global Flash */
 import Helper from '../helpers/repo_helper';
 import Service from '../services/repo_service';
 
diff --git a/app/assets/javascripts/search.js b/app/assets/javascripts/search.js
index 05caf177aec..07fee53d814 100644
--- a/app/assets/javascripts/search.js
+++ b/app/assets/javascripts/search.js
@@ -1,5 +1,5 @@
 /* eslint-disable func-names, space-before-function-paren, wrap-iife, no-var, one-var, one-var-declaration-per-line, object-shorthand, prefer-arrow-callback, comma-dangle, prefer-template, quotes, no-else-return, max-len */
-/* global Flash */
+import Flash from './flash';
 import Api from './api';
 
 (function() {
diff --git a/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees.js b/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees.js
index f83c3b037ed..74c17bc14a2 100644
--- a/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees.js
+++ b/app/assets/javascripts/sidebar/components/assignees/sidebar_assignees.js
@@ -1,5 +1,4 @@
-/* global Flash */
-
+import Flash from '../../../flash';
 import AssigneeTitle from './assignee_title';
 import Assignees from './assignees';
 
diff --git a/app/assets/javascripts/sidebar/components/confidential/confidential_issue_sidebar.vue b/app/assets/javascripts/sidebar/components/confidential/confidential_issue_sidebar.vue
index f2b1099a678..22a9a34dda3 100644
--- a/app/assets/javascripts/sidebar/components/confidential/confidential_issue_sidebar.vue
+++ b/app/assets/javascripts/sidebar/components/confidential/confidential_issue_sidebar.vue
@@ -1,5 +1,5 @@
 <script>
-/* global Flash */
+import Flash from '../../../flash';
 import editForm from './edit_form.vue';
 
 export default {
diff --git a/app/assets/javascripts/sidebar/lib/sidebar_move_issue.js b/app/assets/javascripts/sidebar/lib/sidebar_move_issue.js
index 3c9de02407e..977dd83a7ea 100644
--- a/app/assets/javascripts/sidebar/lib/sidebar_move_issue.js
+++ b/app/assets/javascripts/sidebar/lib/sidebar_move_issue.js
@@ -1,5 +1,3 @@
-/* global Flash */
-
 function isValidProjectId(id) {
   return id > 0;
 }
@@ -38,7 +36,7 @@ class SidebarMoveIssue {
       data: (searchTerm, callback) => {
         this.mediator.fetchAutocompleteProjects(searchTerm)
           .then(callback)
-          .catch(() => new Flash('An error occurred while fetching projects autocomplete.'));
+          .catch(() => new window.Flash('An error occurred while fetching projects autocomplete.'));
       },
       renderRow: project => `
         <li>
@@ -73,7 +71,7 @@ class SidebarMoveIssue {
 
       this.mediator.moveIssue()
         .catch(() => {
-          Flash('An error occurred while moving the issue.');
+          window.Flash('An error occurred while moving the issue.');
           this.$confirmButton
             .enable()
             .removeClass('is-loading');
diff --git a/app/assets/javascripts/sidebar/sidebar_mediator.js b/app/assets/javascripts/sidebar/sidebar_mediator.js
index 2fe6e5b31f0..ede3a0de144 100644
--- a/app/assets/javascripts/sidebar/sidebar_mediator.js
+++ b/app/assets/javascripts/sidebar/sidebar_mediator.js
@@ -1,5 +1,4 @@
-/* global Flash */
-
+import Flash from '../flash';
 import Service from './services/sidebar_service';
 import Store from './stores/sidebar_store';
 
diff --git a/app/assets/javascripts/star.js b/app/assets/javascripts/star.js
index 3a06b477d7c..77db075d1ef 100644
--- a/app/assets/javascripts/star.js
+++ b/app/assets/javascripts/star.js
@@ -1,6 +1,5 @@
 /* eslint-disable func-names, space-before-function-paren, wrap-iife, no-unused-vars, one-var, no-var, one-var-declaration-per-line, prefer-arrow-callback, no-new, max-len */
-/* global Flash */
-
+import Flash from './flash';
 import { __, s__ } from './locale';
 
 export default class Star {
diff --git a/app/assets/javascripts/task_list.js b/app/assets/javascripts/task_list.js
index c39f569da5e..dcbec40c79e 100644
--- a/app/assets/javascripts/task_list.js
+++ b/app/assets/javascripts/task_list.js
@@ -1,6 +1,5 @@
-/* global Flash */
-
 import 'deckar01-task_list';
+import Flash from './flash';
 
 export default class TaskList {
   constructor(options = {}) {
diff --git a/app/assets/javascripts/vue_merge_request_widget/components/mr_widget_deployment.js b/app/assets/javascripts/vue_merge_request_widget/components/mr_widget_deployment.js
index e98d147733c..e86a0f7e749 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/mr_widget_deployment.js
+++ b/app/assets/javascripts/vue_merge_request_widget/components/mr_widget_deployment.js
@@ -1,6 +1,5 @@
-/* global Flash */
-
 import '~/lib/utils/datetime_utility';
+import Flash from '../../flash';
 import MemoryUsage from './mr_widget_memory_usage';
 import StatusIcon from './mr_widget_status_icon';
 import MRWidgetService from '../services/mr_widget_service';
diff --git a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merge_when_pipeline_succeeds.js b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merge_when_pipeline_succeeds.js
index bdfd4d9667c..05c4a28be88 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merge_when_pipeline_succeeds.js
+++ b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merge_when_pipeline_succeeds.js
@@ -1,4 +1,4 @@
-/* global Flash */
+import Flash from '../../../flash';
 import statusIcon from '../mr_widget_status_icon';
 import MRWidgetAuthor from '../../components/mr_widget_author';
 import eventHub from '../../event_hub';
diff --git a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merged.js b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merged.js
index 74fc52796a0..2dfd87ed904 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merged.js
+++ b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_merged.js
@@ -1,5 +1,4 @@
-/* global Flash */
-
+import Flash from '../../../flash';
 import mrWidgetAuthorTime from '../../components/mr_widget_author_time';
 import tooltip from '../../../vue_shared/directives/tooltip';
 import loadingIcon from '../../../vue_shared/components/loading_icon.vue';
diff --git a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_ready_to_merge.js b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_ready_to_merge.js
index 61734163b6e..b8a96b23012 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_ready_to_merge.js
+++ b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_ready_to_merge.js
@@ -1,7 +1,7 @@
-/* global Flash */
 import successSvg from 'icons/_icon_status_success.svg';
 import warningSvg from 'icons/_icon_status_warning.svg';
 import simplePoll from '~/lib/utils/simple_poll';
+import Flash from '../../../flash';
 import statusIcon from '../mr_widget_status_icon';
 import eventHub from '../../event_hub';
 
diff --git a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_wip.js b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_wip.js
index 54be1fbe675..4f83350e07c 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_wip.js
+++ b/app/assets/javascripts/vue_merge_request_widget/components/states/mr_widget_wip.js
@@ -1,4 +1,3 @@
-/* global Flash */
 import statusIcon from '../mr_widget_status_icon';
 import tooltip from '../../../vue_shared/directives/tooltip';
 import eventHub from '../../event_hub';
@@ -27,12 +26,12 @@ export default {
         .then(res => res.json())
         .then((res) => {
           eventHub.$emit('UpdateWidgetData', res);
-          new Flash('The merge request can now be merged.', 'notice'); // eslint-disable-line
+          new window.Flash('The merge request can now be merged.', 'notice'); // eslint-disable-line
           $('.merge-request .detail-page-description .title').text(this.mr.title);
         })
         .catch(() => {
           this.isMakingRequest = false;
-          new Flash('Something went wrong. Please try again.'); // eslint-disable-line
+          new window.Flash('Something went wrong. Please try again.'); // eslint-disable-line
         });
     },
   },
diff --git a/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js b/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js
index 044b664484b..4f497b204a3 100644
--- a/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js
+++ b/app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js
@@ -1,5 +1,4 @@
-/* global Flash */
-
+import Flash from '../flash';
 import {
   WidgetHeader,
   WidgetMergeHelp,
diff --git a/app/assets/javascripts/vue_shared/components/markdown/field.vue b/app/assets/javascripts/vue_shared/components/markdown/field.vue
index 759d30c9c7c..af4187fab46 100644
--- a/app/assets/javascripts/vue_shared/components/markdown/field.vue
+++ b/app/assets/javascripts/vue_shared/components/markdown/field.vue
@@ -1,5 +1,5 @@
 <script>
-  /* global Flash */
+  import Flash from '../../../flash';
   import markdownHeader from './header.vue';
   import markdownToolbar from './toolbar.vue';
 
diff --git a/spec/javascripts/flash_spec.js b/spec/javascripts/flash_spec.js
new file mode 100644
index 00000000000..060ffaa339b
--- /dev/null
+++ b/spec/javascripts/flash_spec.js
@@ -0,0 +1,269 @@
+import flash, {
+  createFlashEl,
+  createAction,
+  hideFlash,
+} from '~/flash';
+
+describe('Flash', () => {
+  describe('createFlashEl', () => {
+    let el;
+
+    beforeEach(() => {
+      el = document.createElement('div');
+    });
+
+    afterEach(() => {
+      el.innerHTML = '';
+    });
+
+    it('creates flash element with type', () => {
+      el.innerHTML = createFlashEl('testing', 'alert');
+
+      expect(
+        el.querySelector('.flash-alert'),
+      ).not.toBeNull();
+    });
+
+    it('escapes text', () => {
+      el.innerHTML = createFlashEl('<script>alert("a");</script>', 'alert');
+
+      expect(
+        el.querySelector('.flash-text').textContent.trim(),
+      ).toBe('<script>alert("a");</script>');
+    });
+
+    it('adds container classes when inside content wrapper', () => {
+      el.innerHTML = createFlashEl('testing', 'alert', true);
+
+      expect(
+        el.querySelector('.flash-text').classList.contains('container-fluid'),
+      ).toBeTruthy();
+      expect(
+        el.querySelector('.flash-text').classList.contains('container-limited'),
+      ).toBeTruthy();
+    });
+  });
+
+  describe('hideFlash', () => {
+    let el;
+
+    beforeEach(() => {
+      el = document.createElement('div');
+      el.className = 'js-testing';
+    });
+
+    it('sets transition style', () => {
+      hideFlash(el);
+
+      expect(
+        el.style.transition,
+      ).toBe('opacity 0.3s');
+    });
+
+    it('sets opacity style', () => {
+      hideFlash(el);
+
+      expect(
+        el.style.opacity,
+      ).toBe('0');
+    });
+
+    it('does not set styles when fadeTransition is false', () => {
+      hideFlash(el, false);
+
+      expect(
+        el.style.opacity,
+      ).toBe('');
+      expect(
+        el.style.transition,
+      ).toBe('');
+    });
+
+    it('removes element after transitionend', () => {
+      document.body.appendChild(el);
+
+      hideFlash(el);
+      el.dispatchEvent(new Event('transitionend'));
+
+      expect(
+        document.querySelector('.js-testing'),
+      ).toBeNull();
+    });
+
+    it('calls event listener callback once', () => {
+      spyOn(el, 'remove').and.callThrough();
+      document.body.appendChild(el);
+
+      hideFlash(el);
+
+      el.dispatchEvent(new Event('transitionend'));
+      el.dispatchEvent(new Event('transitionend'));
+
+      expect(
+        el.remove.calls.count(),
+      ).toBe(1);
+    });
+  });
+
+  describe('createAction', () => {
+    let el;
+
+    beforeEach(() => {
+      el = document.createElement('div');
+    });
+
+    it('creates link with href', () => {
+      el.innerHTML = createAction({
+        href: 'testing',
+        title: 'test',
+      });
+
+      expect(
+        el.querySelector('.flash-action').href,
+      ).toContain('testing');
+    });
+
+    it('uses hash as href when no href is present', () => {
+      el.innerHTML = createAction({
+        title: 'test',
+      });
+
+      expect(
+        el.querySelector('.flash-action').href,
+      ).toContain('#');
+    });
+
+    it('adds role when no href is present', () => {
+      el.innerHTML = createAction({
+        title: 'test',
+      });
+
+      expect(
+        el.querySelector('.flash-action').getAttribute('role'),
+      ).toBe('button');
+    });
+
+    it('escapes the title text', () => {
+      el.innerHTML = createAction({
+        title: '<script>alert("a")</script>',
+      });
+
+      expect(
+        el.querySelector('.flash-action').textContent.trim(),
+      ).toBe('<script>alert("a")</script>');
+    });
+  });
+
+  describe('createFlash', () => {
+    describe('no flash-container', () => {
+      it('does not add to the DOM', () => {
+        const flashEl = flash('testing');
+
+        expect(
+          flashEl,
+        ).toBeNull();
+        expect(
+          document.querySelector('.flash-alert'),
+        ).toBeNull();
+      });
+    });
+
+    describe('with flash-container', () => {
+      beforeEach(() => {
+        document.body.innerHTML += `
+          <div class="content-wrapper js-content-wrapper">
+            <div class="flash-container"></div>
+          </div>
+        `;
+      });
+
+      afterEach(() => {
+        document.querySelector('.js-content-wrapper').remove();
+      });
+
+      it('adds flash element into container', () => {
+        flash('test');
+
+        expect(
+          document.querySelector('.flash-alert'),
+        ).not.toBeNull();
+      });
+
+      it('adds flash into specified parent', () => {
+        flash(
+          'test',
+          'alert',
+          document.querySelector('.content-wrapper'),
+        );
+
+        expect(
+          document.querySelector('.content-wrapper .flash-alert'),
+        ).not.toBeNull();
+      });
+
+      it('adds container classes when inside content-wrapper', () => {
+        flash('test');
+
+        expect(
+          document.querySelector('.flash-text').className,
+        ).toBe('flash-text container-fluid container-limited');
+      });
+
+      it('does not add container when outside of content-wrapper', () => {
+        document.querySelector('.content-wrapper').className = 'js-content-wrapper';
+        flash('test');
+
+        expect(
+          document.querySelector('.flash-text').className.trim(),
+        ).toBe('flash-text');
+      });
+
+      it('removes element after clicking', () => {
+        flash('test', 'alert', document, null, false);
+
+        document.querySelector('.flash-alert').click();
+
+        expect(
+          document.querySelector('.flash-alert'),
+        ).toBeNull();
+      });
+
+      describe('with actionConfig', () => {
+        it('adds action link', () => {
+          flash(
+            'test',
+            'alert',
+            document,
+            {
+              title: 'test',
+            },
+          );
+
+          expect(
+            document.querySelector('.flash-action'),
+          ).not.toBeNull();
+        });
+
+        it('calls actionConfig clickHandler on click', () => {
+          const actionConfig = {
+            title: 'test',
+            clickHandler: jasmine.createSpy('actionConfig'),
+          };
+
+          flash(
+            'test',
+            'alert',
+            document,
+            actionConfig,
+          );
+
+          document.querySelector('.flash-action').click();
+
+          expect(
+            actionConfig.clickHandler,
+          ).toHaveBeenCalled();
+        });
+      });
+    });
+  });
+});
diff --git a/spec/javascripts/integrations/integration_settings_form_spec.js b/spec/javascripts/integrations/integration_settings_form_spec.js
index 3daeb91b1e2..9033eb9ce02 100644
--- a/spec/javascripts/integrations/integration_settings_form_spec.js
+++ b/spec/javascripts/integrations/integration_settings_form_spec.js
@@ -138,9 +138,9 @@ describe('IntegrationSettingsForm', () => {
       deferred.resolve({ error: true, message: errorMessage, service_response: 'some error' });
 
       const $flashContainer = $('.flash-container');
-      expect($flashContainer.find('.flash-text').text()).toEqual('Test failed. some error');
+      expect($flashContainer.find('.flash-text').text().trim()).toEqual('Test failed. some error');
       expect($flashContainer.find('.flash-action')).toBeDefined();
-      expect($flashContainer.find('.flash-action').text()).toEqual('Save anyway');
+      expect($flashContainer.find('.flash-action').text().trim()).toEqual('Save anyway');
     });
 
     it('should submit form if ajax request responds without any error in test', () => {
@@ -168,7 +168,7 @@ describe('IntegrationSettingsForm', () => {
       expect($flashAction).toBeDefined();
 
       spyOn(integrationSettingsForm.$form, 'submit');
-      $flashAction.trigger('click');
+      $flashAction.get(0).click();
       expect(integrationSettingsForm.$form.submit).toHaveBeenCalled();
     });
 
@@ -181,7 +181,7 @@ describe('IntegrationSettingsForm', () => {
 
       deferred.reject();
 
-      expect($('.flash-container .flash-text').text()).toEqual(errorMessage);
+      expect($('.flash-container .flash-text').text().trim()).toEqual(errorMessage);
     });
 
     it('should always call `toggleSubmitBtnState` with `false` once request is completed', () => {
diff --git a/spec/javascripts/notes_spec.js b/spec/javascripts/notes_spec.js
index 3e791a31604..65d2e8fd9fb 100644
--- a/spec/javascripts/notes_spec.js
+++ b/spec/javascripts/notes_spec.js
@@ -815,7 +815,7 @@ import '~/notes';
       });
 
       it('shows a flash message', () => {
-        this.notes.addFlash('Error message', FLASH_TYPE_ALERT, this.notes.parentTimeline);
+        this.notes.addFlash('Error message', FLASH_TYPE_ALERT, this.notes.parentTimeline.get(0));
 
         expect($('.flash-alert').is(':visible')).toBeTruthy();
       });
@@ -828,7 +828,7 @@ import '~/notes';
       });
 
       it('hides visible flash message', () => {
-        this.notes.addFlash('Error message 1', FLASH_TYPE_ALERT, this.notes.parentTimeline);
+        this.notes.addFlash('Error message 1', FLASH_TYPE_ALERT, this.notes.parentTimeline.get(0));
 
         this.notes.clearFlash();