Format a Number, Exactly Two in Length?

Question

I have an integer that is less then 100 and is printed to an HTML page with JavaScript. How do I format the integer so that it is exactly two digits long? For example:

Answer 1

I usually use this function.

function pad(n, len) {
    let l = Math.floor(len)
    let sn = '' + n
    let snl = sn.length
    if(snl >= l) return sn
    return '0'.repeat(l - snl) + sn
}

Usage Example

pad(1, 1)    // ==> returns '1' (string type)
pad(384, 5)  // ==> returns '00384'
pad(384, 4.5)// ==> returns '0384'
pad(5555, 2) // ==> returns '5555'