Test run

vite.config.js

@@ -1,6 +1,7 @@
 import { defineConfig } from 'vite';
 import react from '@vitejs/plugin-react';
 import postcss from './postcss.config.js';
+import path from 'path';
 
 // https://vitejs.dev/config/
 export default defineConfig({
@@ -11,4 +12,16 @@ export default defineConfig({
   css: {
     postcss,
   },
+  build: {
+    lib: {
+      entry: path.resolve(__dirname, 'src/App.jsx'),
+      name: 'MyLib',
+      fileName: (format) => `my-lib.${format}.js`,
+    },
+    rollupOptions: {
+      // make sure to externalize deps that shouldn't be bundled
+      // into your library
+      external: ['react', 'react-dom'],
+    },
+  },
 });