rollup-plugin-commonjs-named-exports

Re-export CommonJS named exports using Node.js cjs-module-lexer.

Useful to allow import { Fragment, useState } from "react"; (instead of forcing import React from "react";) instance for a bundled React as the source package still re-exports its CJS named exports based on process.env.NODE_ENV:

// react/index.js
if (process.env.NODE_ENV === "production") {
  module.exports = require("./cjs/react.production.min.js");
} else {
  module.exports = require("./cjs/react.development.js");
}
// react/cjs/react.development.js
// ...
exports.Fragment = REACT_FRAGMENT_TYPE;
exports.useReducer = useReducer;
exports.useRef = useRef;
exports.useState = useState;
// ...

Based on esinstall and jspm-rollup.

Installation

npm install rollup-plugin-commonjs-named-exports

Usage

Rolldown

No additional plugins required — Rolldown handles CJS conversion natively.

Create a rolldown.config.js configuration file and import the plugin:

import commonjsNamedExports from "rollup-plugin-commonjs-named-exports";

export default {
  input: "src/index.js",
  output: {
    dir: "output",
    format: "es",
  },
  plugins: [commonjsNamedExports()],
};

Rollup

@rollup/plugin-commonjs is still required for the actual CJS→ESM conversion. This plugin only provides the named export declarations on top.

Create a rollup.config.js configuration file and import the plugin:

import commonjs from "@rollup/plugin-commonjs";
import commonjsNamedExports from "rollup-plugin-commonjs-named-exports";

export default {
  input: "src/index.js",
  output: {
    dir: "output",
  },
  plugins: [commonjs(), commonjsNamedExports()],
};

Then call rollup either via the CLI or the API.

Caveats

• Static analysis only: named export detection relies on cjs-module-lexer (the same lexer Node.js uses internally). Modules that assign exports entirely at runtime (e.g. module.exports[key] = value inside a loop) will not have their named exports detected; only the default export will be available.
• Entry points only: the plugin only wraps modules declared as bundle entry points. Non-entry CJS imports inside your source are not affected.
• ESM entries are passed through: if an entry has no statically detectable CJS exports the plugin is a no-op for that entry, leaving it to the bundler's default handling.

License

MIT. See license file.