1 files changed, 43 insertions, 0 deletions
diff --git a/app/assets/javascripts/behaviors/markdown/nodes/table_header_row.js b/app/assets/javascripts/behaviors/markdown/nodes/table_header_row.js
new file mode 100644
index 00000000000..e7eee636402
--- /dev/null
+++ b/app/assets/javascripts/behaviors/markdown/nodes/table_header_row.js
@@ -0,0 +1,43 @@
+/* eslint-disable class-methods-use-this */
+
+import TableRow from './table_row';
+
+const CENTER_ALIGN = 'center';
+
+// Transforms generated HTML back to GFM for Banzai::Filter::MarkdownFilter
+export default class TableHeaderRow extends TableRow {
+  get name() {
+    return 'table_header_row';
+  }
+
+  get schema() {
+    return {
+      content: 'table_cell+',
+      parseDOM: [
+        {
+          tag: 'thead tr',
+          priority: 51,
+        },
+      ],
+      toDOM: () => ['tr', 0],
+    };
+  }
+
+  toMarkdown(state, node) {
+    const cellWidths = super.toMarkdown(state, node);
+
+    state.flushClose(1);
+
+    state.write('|');
+    node.forEach((cell, _, i) => {
+      if (i) state.write('|');
+
+      state.write(cell.attrs.align === CENTER_ALIGN ? ':' : '-');
+      state.write(state.repeat('-', cellWidths[i]));
+      state.write(cell.attrs.align === CENTER_ALIGN || cell.attrs.align === 'right' ? ':' : '-');
+    });
+    state.write('|');
+
+    state.closeBlock(node);
+  }
+}