JSFiddle - React, Tailwind, and code Playground

by isqua

JavaScript

var a = [1, 2, 1, 4, 1, 5, 24, 2, 5, 3, 4, 25, 21, 50, 101, 21, 3];
var hash = [];
var result = [];

a.forEach(function(n) {
    hash[n] = hash[n] || 0;
    hash[n]++;
});

hash.forEach(function(i, n) {
    var j;
    
    if (i) {
        for (j = 0; j < i; j++) {
            result.push(n);
        }
    }
});

console.log(result);