1 files changed, 42 insertions, 1 deletions
diff --git a/app/assets/javascripts/content_editor/extensions/table.js b/app/assets/javascripts/content_editor/extensions/table.js
index 0f0477cba2e..004bb8b815c 100644
--- a/app/assets/javascripts/content_editor/extensions/table.js
+++ b/app/assets/javascripts/content_editor/extensions/table.js
@@ -1 +1,42 @@
-export { Table as default } from '@tiptap/extension-table';
+import { Table } from '@tiptap/extension-table';
+import { debounce } from 'lodash';
+import { __ } from '~/locale';
+import { getMarkdownSource } from '../services/markdown_sourcemap';
+import { shouldRenderHTMLTable } from '../services/serialization_helpers';
+
+let alertShown = false;
+const onUpdate = debounce((editor) => {
+  if (alertShown) return;
+
+  editor.state.doc.descendants((node) => {
+    if (node.type.name === 'table' && node.attrs.isMarkdown && shouldRenderHTMLTable(node)) {
+      editor.emit('alert', {
+        message: __(
+          'The content editor may change the markdown formatting style of the document, which may not match your original markdown style.',
+        ),
+        variant: 'warning',
+      });
+
+      alertShown = true;
+
+      return false;
+    }
+
+    return true;
+  });
+}, 1000);
+
+export default Table.extend({
+  addAttributes() {
+    return {
+      isMarkdown: {
+        default: null,
+        parseHTML: (element) => Boolean(getMarkdownSource(element)),
+      },
+    };
+  },
+
+  onUpdate({ editor }) {
+    onUpdate(editor);
+  },
+});