From b0e6d962340752137dac53d067c4038d19e89006 Mon Sep 17 00:00:00 2001
From: Raunak Raj <71929976+bajrangCoder@users.noreply.github.com>
Date: Tue, 22 Sep 2026 09:59:24 +0530
Subject: [PATCH] feat(editor): enable GFM syntax for Markdown mode

---
 src/cm/supportedModes.ts    |  8 ++++++++
 tests/unit/modelist.test.js | 24 ++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/src/cm/supportedModes.ts b/src/cm/supportedModes.ts
index 31a34ff1d..959386be9 100644
--- a/src/cm/supportedModes.ts
+++ b/src/cm/supportedModes.ts
@@ -72,6 +72,14 @@ function createLanguageLoader(name: string, lang: LanguageDescription) {
 				return javascript({ jsx: true });
 			};
 
+		case "markdown":
+			return async () => {
+				const { markdown, markdownLanguage } = await import(
+					"@codemirror/lang-markdown"
+				);
+				return markdown({ base: markdownLanguage });
+			};
+
 		case "html":
 			return async () => {
 				const { html } = await import("@codemirror/lang-html");
diff --git a/tests/unit/modelist.test.js b/tests/unit/modelist.test.js
index beab91278..30fece635 100644
--- a/tests/unit/modelist.test.js
+++ b/tests/unit/modelist.test.js
@@ -147,6 +147,30 @@ function registerTestMode(name, extensions, options) {
 }
 
 describe("getModeForPath", () => {
+	it("loads Markdown with extended GFM syntax", async () => {
+		const markdownMode = getModeForPath("README.md");
+		const loadMarkdown = markdownMode.getExtension();
+		expect(loadMarkdown).toEqual(expect.any(Function));
+
+		const support = await loadMarkdown();
+		const tree = support.language.parser.parse(
+			[
+				"~~Strikethrough~~",
+				"",
+				"- [x] Completed task",
+				"",
+				"| Column 1 | Column 2 |",
+				"|----------|----------|",
+				"| A        | B        |",
+			].join("\n"),
+		);
+		const syntax = tree.toString();
+
+		expect(syntax).toContain("Strikethrough");
+		expect(syntax).toContain("TaskMarker");
+		expect(syntax).toContain("Table");
+	});
+
 	it("matches the previous sort-and-scan result for built-in modes", () => {
 		const paths = collectParityPaths();
 		expect(paths.length).toBeGreaterThan(100);