fix: double export default for txt files

Author: sapphi-red

packages/vite/src/node/plugins/asset.ts

@@ -174,9 +174,12 @@ export function assetPlugin(config: ResolvedConfig): Plugin {
         const file = checkPublicFile(id, config) || cleanUrl(id)
         this.addWatchFile(file)
         // raw query, read file and return as string
-        return `export default ${JSON.stringify(
-          await fsp.readFile(file, 'utf-8'),
-        )}`
+        return {
+          code: `export default ${JSON.stringify(
+            await fsp.readFile(file, 'utf-8'),
+          )}`,
+          moduleType: 'js', // NOTE: needs to be set to avoid double `export default` in `?raw&.txt`s
+        }
       }
 
       if (!urlRE.test(id) && !config.assetsInclude(cleanUrl(id))) {
@@ -207,6 +210,7 @@ export function assetPlugin(config: ResolvedConfig): Plugin {
             ? 'no-treeshake'
             : false,
         meta: config.command === 'build' ? { 'vite:asset': true } : undefined,
+        moduleType: 'js', // NOTE: needs to be set to avoid double `export default` in `.txt`s
       }
     },