how to import a CommonJS module as an ECMAScript module All In One

CJS vs ESM

.mjs import .cjs module

cjs-module.cjs

const sum = (a, b) => a + b;

// export = sum;
// 'export =' can only be used in TypeScript files.ts(8003)

// ❌
// exports = sum;
// obj = {}
// sum = undefined

// ✅
// exports.sum = sum;
// console.log(`module inner sum`, sum);

// ✅
// module.exports = sum;
// ✅
module.exports = {sum};

esm-module.mjs

export const Add = (a, b) => a + b;

// ✅
// export default Add;

// ✅
export default {Add};

index.mjs

const log = console.log;

// ESM ✅
// import Add from './esm-module.mjs';
// import {Add as add} from './esm-module.mjs';
// log(`Add =`, Add);
// // Add = [Function: Add]
// log(`add =`, add);
// // add = [Function: Add]

import ESM from './esm-module.mjs';
import {Add as add} from './esm-module.mjs';
log(`ESM =`, ESM);
// ESM = { Add: [Function: Add] }
log(`add =`, add);
// add = [Function: Add]

const test1 = ESM.Add(3,4);
const test2 = add(3,4);

if(test1 === 7 && test2 === 7) {
  log(`

标签：CommonJS,const,sum,mdx,module,how,Add,import	

From： https://www.cnblogs.com/xgqfrms/p/16964865.html