radix.js

function radix(arr) {
    let change = false;
    let mask = 1
    let res = new Array(arr.length)

    do {
        mask = mask * 10
        const bucket = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
        const res = new Array(arr.length)
        change = false
        
        // counting
        arr.forEach(el => {
            if ((mask / 10) < el) {
                let d = Math.floor((el % mask) / (mask/10))
                bucket[d]++
                change = true
            } else {
                bucket[0]++
            }
        })

        if (change === false) break

        // prepare indices
        bucket.forEach((e, i) => i ? bucket[i] = bucket[i-1] + bucket[i] : bucket[i])

        // reorder
        arr.reverse().forEach(el => {
            let d = ((mask / 10) < el) ?  Math.floor(el % mask / ( mask / 10 )) : 0
            bucket[d]--
            res[bucket[d]] = el
        })

        // assert length is correct !
        if (arr.length !== res.length) 
            throw "bucket length differs from res length"

        arr = res   // this is not a deep copy, but a reference assignment!
        // console.log(arr)
    } while (change)

    return arr
}

console.log(
  radix(
    [412, 64, 331, 56, 83, 101, 11, 2]))

console.log("done")
//  0 1 2 3 4 5 6 7 8 9  << i
//    3 2   1   1        << bucket[i]

//  0 3 5