JSFiddle - React, Tailwind, and code Playground

HTML

Result: <pre id="output"></pre>

JavaScript

function isNumber(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}

function isInt(n) {
  return isNumber(n) && n % 1 === 0;
}

var array = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];

var result = array.filter(function(x) {
  return isInt(x);
});

document.querySelector('#output').innerHTML = JSON.stringify(result, null, 4);