core: add contest invitation code

packages/ui-default/components/contest/contest.page.js

@@ -0,0 +1,24 @@
+import { AutoloadPage } from 'vj/misc/Page';
+import delay from 'vj/utils/delay';
+import i18n from 'vj/utils/i18n';
+import request from 'vj/utils/request';
+import Notification from 'vj/components/notification';
+
+const contestPage = new AutoloadPage('contestPage', () => {
+    $('[data-contest-code]').on('click', (ev) => {
+        ev.preventDefault();
+        // eslint-disable-next-line no-alert
+        const code = prompt(i18n('Invitation code:'));
+        request.post('', {
+            operation: 'attend',
+            code,
+        }).then(() => {
+            Notification.success(i18n('Successfully attended'));
+            delay(1000).then(() => window.location.reload());
+        }).catch((e) => {
+            Notification.error(e.message || e);
+        });
+    });
+});
+
+export default contestPage;