JSFiddle - React, Tailwind, and code Playground

JavaScript

var array = ['13', '4', '1', '1', '4', '2', '3', '4', '4', '1', '2', '4', '9', '3'];
 var found = _.chain(array).countBy().pairs().max(_.last);

  var valueOfFrequent = found.head().value();
  var numberOfFrequent = found.tail().value();

  alert("number '" + valueOfFrequent + "' time of frequent: " + numberOfFrequent );