babel-plugin-node-cjs-interop, swc-plugin-node-cjs-interop and node-cjs-interop: fix the default import interoperability issue in Node.js

The problem to solve

Consider the following modules:

// a.js

export default function greet() {
  console.log("Hello, world!");
}

// b.js

import greet from "a.js";

greet();

They usually work, unless the following conditions are met:

• a.js (the module being imported) is a simulated ESM. That is, the module is transpiled as a CommonJS module (by Babel or TypeScript) before execution. And,
• b.js (the importing module) is a native ESM, That is, the module is run on Node.js' native ES Module support.

You can reproduce the above condition by placing the following files:

// a.cjs

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true,
});
exports.default = greet;

function greet() {
  console.log("Hello, world!");
}

// b.mjs

import greet from "./a.cjs";

greet();

$ node ./b.mjs
./b.mjs:3
greet();
^

TypeError: greet is not a function
    at ./b.mjs:3:1
    at ModuleJob.run (node:internal/modules/esm/module_job:185:25)
    at async Promise.all (index 0)
    at async ESMLoader.import (node:internal/modules/esm/loader:281:24)
    at async loadESM (node:internal/process/esm_loader:88:5)
    at async handleMainPromise (node:internal/modules/run_main:65:12)

Solution 1: Babel/SWC plugin

Install the babel plugin:

npm install -D babel-plugin-node-cjs-interop
# or:
yarn add -D babel-plugin-node-cjs-interop

Configure it in your Babel configuration:

// .babelrc.js or babel.config.js

export default {
  presets: [
    /* ... */
  ],
  plugins: [
    // ...
    [
      "babel-plugin-node-cjs-interop",
      {
        packages: ["styled-components", "@babel/helper-plugin-test-runner"],
      },
    ],
  ],
};

See the package's README for details.

SWC version

There is the plugin for SWC too. See the package's README for details.

Solution 2: manually inserting the wrapper

npm install -D node-cjs-interop
# or:
yarn add -D node-cjs-interop

import styledOrig from "styled-components";
import { interopImportCJSDefault } from "node-cjs-interop";

const styled = interopImportCJSDefault(styledOrig);

See the package's README for details.