Modules

Node Modules - CJS

node-modules
├── lib.js
└── main.js

node-modules/lib.js:

function sum(a, b) {
  return a + b;
}

module.exports = sum;

node-modules/main.js:

const sum = require('./lib.js');

console.log(sum(1, 2)); //=> 3


$ node main.js

ECMAScript Modules

Default export

default-export
├── lib.mjs
└── main.mjs

node-esm/default-export/lib.mjs:

export default function sum(x, y) {
  return x + y;
}

node-esm/default-export/main.mjs:

import sum from './lib.mjs';

console.log(sum(10, 5)); //=> 15


$ node --experimental-modules main.mjs

Default and named exports

default-named-exports
├── lib.mjs
└── main.mjs

node-esm/default-named-exports/lib.mjs:

export default function sum(x, y) {
  return x + y;
}

export function minus(x, y) {
  return x - y;
}

node-esm/default-named-exports/main.mjs:

import sum, { minus } from './lib.mjs';

console.log(sum(10, 5)); //=> 15
console.log(minus(10, 5)); //=> 5


$ node --experimental-modules main.mjs

Named as exports

default-as-exports
├── lib.mjs
└── main.mjs

node-esm/named-as-exports/lib.mjs:

export function sum(x, y) {
  return x + y;
}

export function minus(x, y) {
  return x - y;
}

node-esm/named-as-exports/main.mjs:

import * as lib from './lib.mjs';

console.log(lib.sum(10, 5)); //=> 15
console.log(lib.minus(10, 5)); //=> 5


$ node --experimental-modules main.mjs

Named export

named-export
├── lib.mjs
└── main.mjs

node-esm/named-export/lib.mjs:

export function sum(a, b) {
  return a + b;
}

node-esm/named-export/main.mjs:

import { sum } from './lib.mjs';

console.log(sum(1, 2)); //=> 3


$ node --experimental-modules main.mjs

Named exports

named-exports
├── lib.mjs
└── main.mjs

node-esm/named-exports/lib.mjs:

export function sum(x, y) {
  return x + y;
}

export function minus(x, y) {
  return x - y;
}

node-esm/named-exports/main.mjs:

import { sum, minus } from './lib.mjs';

console.log(sum(10, 5)); //=> 15
console.log(minus(10, 5)); //=> 5


$ node --experimental-modules main.mjs

Named uniq export

named-uniq-export
├── lib.mjs
└── main.mjs

node-esm/named-uniq-export/lib.mjs:

function sum(x, y) {
  return x + y;
}

function minus(x, y) {
  return x - y;
}

export { sum, minus };

node-esm/named-uniq-export/main.mjs:

import { sum, minus } from './lib.mjs';

console.log(sum(10, 5)); //=> 15
console.log(minus(10, 5)); //=> 5


$ node --experimental-modules main.mjs

Named uniq export alias

named-uniq-export-alias
├── lib.mjs
└── main.mjs

node-esm/named-uniq-export-alias/lib.mjs:

const squareRoot = Math.sqrt;

function sum(x, y) {
  return x + y;
}

function minus(x, y) {
  return x - y;
}

export { sum, minus, squareRoot as sqrt };

node-esm/named-uniq-export-alias/main.mjs:

import { sum, sqrt } from './lib.mjs';

console.log(sum(10, 5)); //=> 15
console.log(sqrt(100)); //=> 10


$ node --experimental-modules main.mjs

References