plugin-commonjs is useless for node_modules file

[jiayechao]

i use @rollup/plugin-commonjs in vite

create a file named src/tool.js,
exports["default"] = 3

and import in App.vue

import a from './tool.js'
console.log(a) // {default: 3}

but same file in node_module is useless

import a from 'user.js' // tool.js in node_modules but wrong
// The requested module '/node_modules/user.js?v=313d6f97' does not provide an export named 'default'

[potatohoney-p]

The include in the screenshot is a filesystem filter, not a Vite URL. /node_modules/user.js does not match a resolved ID such as /your/project/node_modules/user.js.

I reproduced the raw exports["default"] = 3 response using Vite 4.1.1, CommonJS 24.0.1 and node-resolve 15.0.1 with that filter. Importing that response as ESM produces the missing-default-export error. Changing the filter to **/node_modules/user.js alone was not a complete dev-server fix in this test: it then failed to resolve the generated CommonJS helper module.

For a file you own, keep it in src and use native ESM:

// src/tool.js
export default 3;

// App.vue
import a from './tool.js';
console.log(a); // 3

If you need the original { default: 3 } object, use export default { default: 3 } instead.

For an actual CommonJS dependency, install it as a package with a resolvable entry rather than putting a loose JS file directly into node_modules. Let Vite pre-bundle it; if necessary, explicitly include the package name:

export default defineConfig({
  plugins: [vue()],
  optimizeDeps: { include: ['your-package-name'] },
});

A local fixture package with main: "index.cjs" containing your exports["default"] = 3 code pre-bundled successfully, and its default import evaluated to { default: 3 }. Restart with vite --force after changing dependency configuration.

Vite 4's dependency-prebundling guide explains the dev-time esbuild conversion versus production CommonJS handling. These checks cover the small reproduction and generated module, not your complete Vue application; the original dependency versions weren't provided.