Export shared code between Browser and Node (ESM/CJS dual export)

export-for-browser-and-node.js

/* Export a file to be imported by both Node and Browser.
 *
 * module.exports = sharedFunction;
 * AND
 * export default sharedFunction;
 */

// shared-code.js
function sharedFunction(x) {
  return x * 2;
}

Object.defineProperty(exports, '__esModule', {
  value: true,
});

exports.default = sharedFunction;


/*** Importing in Node (CommonJS) ***/
const sharedFunction = require('shared-code.js').default;

/*** Importing in the Browser (ES Modules) ***/
import sharedFunction from './shared-code.js';