JSFiddle - React, Tailwind, and code Playground

JavaScript

function primeAlert(n) {
  'use strict';
  var arr, m, p, r;
  n = Math.floor(+n);
  if (n !== n || n < 2 || n >= Math.pow(2, 53)) return [];
  arr = [];
  for (m = 2; m < n; m++) {
    p = 1;
    r = Math.sqrt(m);
    while (m % ++p && p <= r);
    if (p > r) arr.push(m);
  }
  return arr;
}