hack together preval plugin

packages/docs-new/plugins/preval.ts

@@ -0,0 +1,40 @@
+import { unlink, writeFile } from "node:fs/promises"
+import type { Plugin } from "vite"
+import { transformWithEsbuild } from "vite"
+
+const prevalPattern = /\.preval\.(js|ts|jsx|tsx|mts|cts)$/
+
+export function preval(): Plugin {
+  return {
+    name: "preval",
+    enforce: "pre",
+
+    async transform(code, filePath) {
+      if (!prevalPattern.test(filePath)) return
+
+      const tempFilePath = `${filePath}.preval.mjs`
+
+      try {
+        const transformResult = await transformWithEsbuild(code, filePath, {
+          target: "node16",
+          format: "esm",
+        })
+
+        await writeFile(tempFilePath, transformResult.code)
+        const runResult = await import(tempFilePath)
+
+        const serialized = Object.entries(runResult)
+          .map(([key, value]) => {
+            return key === "default"
+              ? `export default ${JSON.stringify(value)}`
+              : `export const ${key} = ${JSON.stringify(value)}`
+          })
+          .join("\n")
+
+        return serialized + "\n"
+      } finally {
+        await unlink(tempFilePath).catch(console.warn)
+      }
+    },
+  }
+}

packages/docs-new/vite.config.ts

@@ -4,9 +4,13 @@ import react from "@vitejs/plugin-react"
 import remarkFrontmatter from "remark-frontmatter"
 import { defineConfig } from "vite"
 import ssr from "vite-plugin-ssr/plugin"
-import xdm from "xdm/rollup"
+import xdm from "xdm/rollup.js"
+import { preval } from "./plugins/preval"
 
 export default defineConfig({
+  build: {
+    target: ["node16", "chrome89", "firefox89"],
+  },
   plugins: [
     ssr(),
     react(),
@@ -14,6 +18,7 @@ export default defineConfig({
       remarkPlugins: [remarkFrontmatter],
       rehypePlugins: [rehypePrism],
     }),
+    preval(),
   ],
   resolve: {
     alias: {