How to sort an array efficiently

Question

I\'m trying to sort an array [3,3,2,1,3,2,2,2,1] to [1,1,3,3,3,2,2,2,2].

I\'m trying to handle it using object, using the number as key, and th

Answer 1

You could get the count for sorting the array.

const sortNums = array => {
    const count = {};
    for (let v of array) count[v] = (count[v] || 0) + 1;
    return array.sort((a, b) => count[a] - count[b] || a - b);
}

console.log(sortNums([3, 3, 2, 1, 3, 2, 1]));

An approach by using the object for sorting.

const sortNums = array => {
    var count = {},
        result = {};
    for (let v of array) (count[v] = count[v] || []).push(v);
    for (let a of Object.values(count)) (result[a.length] = result[a.length] || []).push(a);
    return Object.values(result).flat(Infinity)
}

console.log(sortNums([3, 3, 2, 1, 3, 2, 1]));