EcmaScript | ES6 modules.js

// lib.js
export const PI = Math.PI
const sum = (a, b) => a + b
export default sum

// file.js
import sum, { PI } from 'lib.js'
console.log(sum(1, PI)) // Expected output: 4.141592654

// lib2.js
export * from 'lib.js'
export const e = Math.E
export const ln = x => Math.log(x)

//file2.js
import * as ma from 'lib2.js'
console.log(ma.ln(ma.e)) // Expected output: 1
console.log(sum(1, PI)) // Expected output: 4.141592654