Markdown and MDX configuration rework (#5684)

* feat: change extendDefaults -> gfm

* deps: remove smartypants from md/remark

* tests: update markdown plugin tests

* fix: borked lockfile

* feat: allow all Markdown options in MDX config, with extend

* deps: remove smartypants from MDX

* chore: remove unused `mode` property

* chore: remark rehype types

* chore: dead code

* fix: order of default config properties

* refactor: move md defaults to remark

* fix: RemarkRehype type

* fix: apply defaults based on MD defaults

* chore: update plugin tests

* chore: add syntaxHighlight test

* refactor: remove drafts from config defaults

* docs: new MDX config options

* chore: add changeset

* edit: test both extends for syntax highlight

* refactor: remove MDX config deep merge

* docs: update README and changeset

* edit: avoid -> disable

Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>

* edit: `drafts` clarification

Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>

* edit: remove "scare quotes"

Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>

* docs: MDX config options redraft

* docs: add migration

* chore: changeset heading levels

* refactor: githubFlavoredMarkdown -> gfm

* chore: remove unused imports

Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>

1 files changed, 26 insertions, 0 deletions

diff --git a/packages/integrations/mdx/test/mdx-syntax-highlighting.test.js b/packages/integrations/mdx/test/mdx-syntax-highlighting.test.js
index 32c6bcd04..d420faabc 100644
--- a/packages/integrations/mdx/test/mdx-syntax-highlighting.test.js
+++ b/packages/integrations/mdx/test/mdx-syntax-highlighting.test.js
@@ -67,6 +67,32 @@ describe('MDX syntax highlighting', () => {
 			const prismCodeBlock = document.querySelector('pre.language-astro');
 			expect(prismCodeBlock).to.not.be.null;
 		});
+
+		for (const extendMarkdownConfig of [true, false]) {
+			it(`respects syntaxHighlight when extendMarkdownConfig = ${extendMarkdownConfig}`, async () => {
+				const fixture = await loadFixture({
+					root: FIXTURE_ROOT,
+					markdown: {
+						syntaxHighlight: 'shiki',
+					},
+					integrations: [
+						mdx({
+							extendMarkdownConfig,
+							syntaxHighlight: 'prism',
+						}),
+					],
+				});
+				await fixture.build();
+
+				const html = await fixture.readFile('/index.html');
+				const { document } = parseHTML(html);
+
+				const shikiCodeBlock = document.querySelector('pre.astro-code');
+				expect(shikiCodeBlock, 'Markdown config syntaxHighlight used unexpectedly').to.be.null;
+				const prismCodeBlock = document.querySelector('pre.language-astro');
+				expect(prismCodeBlock).to.not.be.null;
+			});
+		}
 	});
 
 	it('supports custom highlighter - shiki-twoslash', async () => {