Log hello message in browser console

app/assets/javascripts/lib/logger/hello.js

+const HANDSHAKE = String.fromCodePoint(0x1f91d);
+const MAG = String.fromCodePoint(0x1f50e);
+
+export const logHello = () => {
+  // eslint-disable-next-line no-console
+  console.log(
+    `%cWelcome to GitLab!%c
+
+Does this page need fixes or improvements? Open an issue or contribute a merge request to help make GitLab more lovable. At GitLab, everyone can contribute!
+
+${HANDSHAKE} Contribute to GitLab: https://about.gitlab.com/community/contribute/
+${MAG} Create a new GitLab issue: https://gitlab.com/gitlab-org/gitlab/-/issues/new`,
+    `padding-top: 0.5em; font-size: 2em;`,
+    'padding-bottom: 0.5em;',
+  );
+};

app/assets/javascripts/lib/logger/hello_deferred.js

+export const logHelloDeferred = async () => {
+  const { logHello } = await import(/* webpackChunkName: 'hello' */ './hello');
+
+  logHello();
+};

app/assets/javascripts/main.js

@@ -19,6 +19,7 @@ import initAlertHandler from './alert_handler';
 import { removeFlashClickListener } from './flash';
 import initTodoToggle from './header';
 import initLayoutNav from './layout_nav';
+import { logHelloDeferred } from './lib/logger/hello_deferred';
 import { handleLocationHash, addSelectOnFocusBehaviour } from './lib/utils/common_utils';
 import { localTimeAgo } from './lib/utils/datetime/timeago_utility';
 import { getLocationHash, visitUrl } from './lib/utils/url_utility';
@@ -40,6 +41,8 @@ import { initHeaderSearchApp } from '~/header_search';
 import 'ee_else_ce/main_ee';
 import 'jh_else_ce/main_jh';
 
+logHelloDeferred();
+
 applyGitLabUIConfig();
 
 // expose jQuery as global (TODO: remove these)

spec/frontend/lib/logger/__snapshots__/hello_spec.js.snap

+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`~/lib/logger/hello logHello console logs a friendly hello message 1`] = `
+Array [
+  Array [
+    "%cWelcome to GitLab!%c
+
+Does this page need fixes or improvements? Open an issue or contribute a merge request to help make GitLab more lovable. At GitLab, everyone can contribute!
+
+🤝 Contribute to GitLab: https://about.gitlab.com/community/contribute/
+🔎 Create a new GitLab issue: https://gitlab.com/gitlab-org/gitlab/-/issues/new",
+    "padding-top: 0.5em; font-size: 2em;",
+    "padding-bottom: 0.5em;",
+  ],
+]
+`;

spec/frontend/lib/logger/hello_deferred_spec.js

+import waitForPromises from 'helpers/wait_for_promises';
+import { logHello } from '~/lib/logger/hello';
+import { logHelloDeferred } from '~/lib/logger/hello_deferred';
+
+jest.mock('~/lib/logger/hello');
+
+describe('~/lib/logger/hello_deferred', () => {
+  it('dynamically imports and calls logHello', async () => {
+    logHelloDeferred();
+
+    expect(logHello).not.toHaveBeenCalled();
+
+    await waitForPromises();
+
+    expect(logHello).toHaveBeenCalled();
+  });
+});

spec/frontend/lib/logger/hello_spec.js

+import { logHello } from '~/lib/logger/hello';
+
+describe('~/lib/logger/hello', () => {
+  let consoleLogSpy;
+
+  beforeEach(() => {
+    // We don't `mockImplementation` so we can validate there's no errors thrown
+    consoleLogSpy = jest.spyOn(console, 'log');
+  });
+
+  describe('logHello', () => {
+    it('console logs a friendly hello message', () => {
+      expect(consoleLogSpy).not.toHaveBeenCalled();
+
+      logHello();
+
+      expect(consoleLogSpy.mock.calls).toMatchSnapshot();
+    });
+  });
+});