feat: support async markdown transformer

Author: kermanx

packages/slidev/node/vite/markdown.ts

@@ -33,12 +33,12 @@ export async function createMarkdownPlugin(
     },
     transforms: {
       ...mdOptions?.transforms,
-      before(code, id) {
+      async before(code, id) {
         // Skip entry Markdown files
         if (options.data.markdownFiles[id])
           return ''
 
-        code = mdOptions?.transforms?.before?.(code, id) ?? code
+        code = await mdOptions?.transforms?.before?.(code, id) ?? code
 
         const match = id.match(regexSlideSourceId)
         if (!match)
@@ -55,7 +55,7 @@ export async function createMarkdownPlugin(
         for (const transformer of transformers) {
           if (!transformer)
             continue
-          transformer(ctx)
+          await transformer(ctx)
           if (!ctx.s.isEmpty())
             ctx.s.commit()
         }

packages/types/src/transform.ts

@@ -1,3 +1,4 @@
+import type { Awaitable } from '@antfu/utils'
 import type MagicString from 'magic-string-stack'
 import type { ResolvedSlidevOptions } from './options'
 import type { SlideInfo } from './types'
@@ -19,4 +20,4 @@ export interface MarkdownTransformContext {
   options: ResolvedSlidevOptions
 }
 
-export type MarkdownTransformer = (ctx: MarkdownTransformContext) => void
+export type MarkdownTransformer = (ctx: MarkdownTransformContext) => Awaitable<void>

pnpm-lock.yaml

@@ -122,7 +122,7 @@ catalog:
   unocss: ^65.4.0
   unplugin-icons: ^22.0.0
   unplugin-vue-components: ^28.0.0
-  unplugin-vue-markdown: ^28.0.0
+  unplugin-vue-markdown: ^28.1.0
   untun: ^0.1.3
   uqr: ^0.1.2
   vite: ^6.0.7