radixSort.js

function getDigit(n, i) {
    n = Math.abs(n)
    return (n / 10 ** i | 0) % 10
}

function countDigit(n) {
    if (n === 0) {
        return 1
    }
    n = Math.abs(n)
    return Math.ceil(Math.log10(n + 1))
}

function radixSort(integers) {
    let maxDigits = 0 

    for (let n of integers) {
        maxDigits = Math.max(maxDigits, countDigit(n))
    }

    let buckets = [...Array(10)].map(_ => [])
    for (let i = 0; i < maxDigits + 1; i++) {
        for (let n of integers) {
            buckets[getDigit(n, i)].push(n)
        }
        integers = buckets.flat(1)
        buckets = [...Array(10)].map(_ => [])
    }

    return integers
}