fix: preserve comments in frontmatter

.github/workflows/test.yml

@@ -27,5 +27,18 @@ jobs:
         uses: pnpm/[email protected]
         with:
           version: 8
-      - name: Install and run tests
-        run: pnpm it
+      - name: Clone KermanX/slidev
+        run: git clone https://github.com/KermanX/slidev
+        working-directory: ../
+      - name: Install KermanX/slidev
+        run: pnpm i
+        working-directory: ../slidev
+      - name: Build KermanX/slidev
+        run: pnpm build
+        working-directory: ../slidev
+      - name: Install modified version of Slidev
+        run: |
+          pnpm i ../slidev/packages/parser
+          pnpm i -D ../slidev/packages/types
+      - name: Run tests
+        run: pnpm test

README.md

@@ -8,6 +8,11 @@ A [Prettier](https://prettier.io/) plugin for [Slidev](https://sli.dev/).
 npm i -D prettier prettier-plugin-slidev
 ```
 
+Currently, it requires https://github.com/slidevjs/slidev/pull/1268 to run correctly. So you should install `@slidev/parser` and `@slidev/types` from https://github.com/KermanX/slidev/tree/frontmatter-raw :
+
+```sh
+```
+
 ### Activate the plugin
 
 Create or modify your [prettier configuration file](https://prettier.io/docs/en/configuration) to activate the plugin:

src/printer.ts

@@ -45,14 +45,15 @@ async function printFrontmatter(
   info: SlideInfoBase,
   textToDoc: (text: string, options: Options) => Promise<Doc>
 ): Promise<Doc[]> {
-  if (Object.keys(info.frontmatter ?? {}).length === 0) return [];
+  const trimed = info.frontmatterRaw?.trim() ?? "";
+  if (trimed.length === 0) return [];
 
-  const frontmatter = await textToDoc(YAML.dump(info.frontmatter), {
+  const formatted = await textToDoc(trimed, {
     parser: "yaml",
   });
   return info.frontmatterStyle === "yaml"
-    ? [hardline, "```yaml", hardline, frontmatter, hardline, "```", hardline]
-    : [frontmatter, hardline, "---", hardline];
+    ? [hardline, "```yaml", hardline, formatted, hardline, "```", hardline]
+    : [formatted, hardline, "---", hardline];
 }
 
 async function printContent(

test/inputs/tricky.md

@@ -1,5 +1,5 @@
 ---
-a: 1
+a: 1  # hi
 b:             2
 ---
 

test/outputs/tricky_config1.md

@@ -1,7 +1,6 @@
 ---
-a: 1
+a: 1 # hi
 b: 2
-title: Title
 ---
 
 # Title
@@ -11,7 +10,7 @@ title: Title
 | c   | d   |
 
 ---
-layout: abcd
+layout: 'abcd'
 ---
 
 # Title
@@ -70,6 +69,8 @@ b: 2
 let a = '111'
 ```
 
+---
+# empty frontmatter
 ---
 
 # Title

test/outputs/tricky_default.md

@@ -1,7 +1,6 @@
 ---
-a: 1
+a: 1 # hi
 b: 2
-title: Title
 ---
 
 # Title
@@ -11,7 +10,7 @@ title: Title
 | c   | d   |
 
 ---
-layout: abcd
+layout: "abcd"
 ---
 
 # Title
@@ -70,6 +69,8 @@ b: 2
 let a = "111";
 ```
 
+---
+# empty frontmatter
 ---
 
 # Title