main.js

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

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>

info.js

export const name = 'why'
export const age = 25
export const height = 1.88