main.js

const { add, mul } = require('./mathUtils.js')

console.log(add(20, 30))
console.log(mul(20, 30))

import { name, age, height } from "./info"
console.log(name)
console.log(age)
console.log(height)

mainutils.js

function add(num1, num2) {
    return num1 + num2
}

function mul(num1, num2) {
    return num1 * num2
}

module.exports = {
    add,
    mul
}

index.html

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <script src="./dist/bund.js"></script>
</body>

</html>