7 files changed, 97 insertions, 5 deletions
diff --git a/web_src/js/features/common-global.js b/web_src/js/features/common-global.js
index e5fd7c29fc..a99b29141d 100644
--- a/web_src/js/features/common-global.js
+++ b/web_src/js/features/common-global.js
@@ -9,6 +9,7 @@ import {hideElem, showElem, toggleElem} from '../utils/dom.js';
 import {htmlEscape} from 'escape-goat';
 import {createTippy} from '../modules/tippy.js';
 import {confirmModal} from './comp/ConfirmModal.js';
+import {showErrorToast} from '../modules/toast.js';
 
 const {appUrl, appSubUrl, csrfToken, i18n} = window.config;
 
@@ -439,7 +440,7 @@ export function initGlobalButtons() {
       return;
     }
     // should never happen, otherwise there is a bug in code
-    alert('Nothing to hide');
+    showErrorToast('Nothing to hide');
   });
 
   initGlobalShowModal();
diff --git a/web_src/js/features/comp/ComboMarkdownEditor.js b/web_src/js/features/comp/ComboMarkdownEditor.js
index 103e71daae..3d696be75b 100644
--- a/web_src/js/features/comp/ComboMarkdownEditor.js
+++ b/web_src/js/features/comp/ComboMarkdownEditor.js
@@ -8,6 +8,7 @@ import {handleGlobalEnterQuickSubmit} from './QuickSubmit.js';
 import {renderPreviewPanelContent} from '../repo-editor.js';
 import {easyMDEToolbarActions} from './EasyMDEToolbarActions.js';
 import {initTextExpander} from './TextExpander.js';
+import {showErrorToast} from '../../modules/toast.js';
 
 let elementIdCounter = 0;
 
@@ -26,7 +27,7 @@ export function validateTextareaNonEmpty($textarea) {
       $form[0]?.reportValidity();
     } else {
       // The alert won't hurt users too much, because we are dropping the EasyMDE and the check only occurs in a few places.
-      alert('Require non-empty content');
+      showErrorToast('Require non-empty content');
     }
     return false;
   }
diff --git a/web_src/js/features/repo-issue-content.js b/web_src/js/features/repo-issue-content.js
index d66f6ad4a4..fc916aea19 100644
--- a/web_src/js/features/repo-issue-content.js
+++ b/web_src/js/features/repo-issue-content.js
@@ -1,5 +1,6 @@
 import $ from 'jquery';
 import {svg} from '../svg.js';
+import {showErrorToast} from '../modules/toast.js';
 
 const {appSubUrl, csrfToken} = window.config;
 let i18nTextEdited;
@@ -39,12 +40,12 @@ function showContentHistoryDetail(issueBaseUrl, commentId, historyId, itemTitleH
             if (resp.ok) {
               $dialog.modal('hide');
             } else {
-              alert(resp.message);
+              showErrorToast(resp.message);
             }
           });
         }
       } else { // required by eslint
-        window.alert(`unknown option item: ${optionItem}`);
+        showErrorToast(`unknown option item: ${optionItem}`);
       }
     },
     onHide() {
diff --git a/web_src/js/features/repo-issue-list.js b/web_src/js/features/repo-issue-list.js
index 4d61de0ce5..5402f958f2 100644
--- a/web_src/js/features/repo-issue-list.js
+++ b/web_src/js/features/repo-issue-list.js
@@ -4,6 +4,7 @@ import {toggleElem} from '../utils/dom.js';
 import {htmlEscape} from 'escape-goat';
 import {Sortable} from 'sortablejs';
 import {confirmModal} from './comp/ConfirmModal.js';
+import {showErrorToast} from '../modules/toast.js';
 
 function initRepoIssueListCheckboxes() {
   const $issueSelectAll = $('.issue-checkbox-all');
@@ -75,7 +76,7 @@ function initRepoIssueListCheckboxes() {
     ).then(() => {
       window.location.reload();
     }).catch((reason) => {
-      window.alert(reason.responseJSON.error);
+      showErrorToast(reason.responseJSON.error);
     });
   });
 }
diff --git a/web_src/js/modules/toast.js b/web_src/js/modules/toast.js
new file mode 100644
index 0000000000..b0d02dc644
--- /dev/null
+++ b/web_src/js/modules/toast.js
@@ -0,0 +1,60 @@
+import {htmlEscape} from 'escape-goat';
+import {svg} from '../svg.js';
+
+const levels = {
+  info: {
+    icon: 'octicon-check',
+    background: 'var(--color-green)',
+    duration: 2500,
+  },
+  warning: {
+    icon: 'gitea-exclamation',
+    background: 'var(--color-orange)',
+    duration: -1, // requires dismissal to hide
+  },
+  error: {
+    icon: 'gitea-exclamation',
+    background: 'var(--color-red)',
+    duration: -1, // requires dismissal to hide
+  },
+};
+
+// See https://github.com/apvarun/toastify-js#api for options
+async function showToast(message, level, {gravity, position, duration, ...other} = {}) {
+  if (!message) return;
+
+  const {default: Toastify} = await import(/* webpackChunkName: 'toastify' */'toastify-js');
+  const {icon, background, duration: levelDuration} = levels[level ?? 'info'];
+
+  const toast = Toastify({
+    text: `
+      <div class='toast-icon'>${svg(icon)}</div>
+      <div class='toast-body'>${htmlEscape(message)}</div>
+      <button class='toast-close'>${svg('octicon-x')}</button>
+    `,
+    escapeMarkup: false,
+    gravity: gravity ?? 'top',
+    position: position ?? 'center',
+    duration: duration ?? levelDuration,
+    style: {background},
+    ...other,
+  });
+
+  toast.showToast();
+
+  toast.toastElement.querySelector('.toast-close').addEventListener('click', () => {
+    toast.removeElement(toast.toastElement);
+  });
+}
+
+export async function showInfoToast(message, opts) {
+  return await showToast(message, 'info', opts);
+}
+
+export async function showWarningToast(message, opts) {
+  return await showToast(message, 'warning', opts);
+}
+
+export async function showErrorToast(message, opts) {
+  return await showToast(message, 'error', opts);
+}
diff --git a/web_src/js/modules/toast.test.js b/web_src/js/modules/toast.test.js
new file mode 100644
index 0000000000..b691aaebb6
--- /dev/null
+++ b/web_src/js/modules/toast.test.js
@@ -0,0 +1,17 @@
+import {test, expect} from 'vitest';
+import {showInfoToast, showErrorToast, showWarningToast} from './toast.js';
+
+test('showInfoToast', async () => {
+  await showInfoToast('success 😀', {duration: -1});
+  expect(document.querySelector('.toastify')).toBeTruthy();
+});
+
+test('showWarningToast', async () => {
+  await showWarningToast('warning 😐', {duration: -1});
+  expect(document.querySelector('.toastify')).toBeTruthy();
+});
+
+test('showErrorToast', async () => {
+  await showErrorToast('error 🙁', {duration: -1});
+  expect(document.querySelector('.toastify')).toBeTruthy();
+});
diff --git a/web_src/js/standalone/devtest.js b/web_src/js/standalone/devtest.js
new file mode 100644
index 0000000000..d0ca511c0f
--- /dev/null
+++ b/web_src/js/standalone/devtest.js
@@ -0,0 +1,11 @@
+import {showInfoToast, showWarningToast, showErrorToast} from '../modules/toast.js';
+
+document.getElementById('info-toast').addEventListener('click', () => {
+  showInfoToast('success 😀');
+});
+document.getElementById('warning-toast').addEventListener('click', () => {
+  showWarningToast('warning 😐');
+});
+document.getElementById('error-toast').addEventListener('click', () => {
+  showErrorToast('error 🙁');
+});