JSFiddle - React, Tailwind, and code Playground

JavaScript

function convertTime (isoTime) {
  var hours   = parseInt(isoTime.substring(0, 2), 10),
      minutes = parseInt(isoTime.substring(3, 5), 10),
      ampm    = 'am';

  if (hours == 12) {
    ampm = 'pm';
  } else if (hours == 0) {
    hours = 12;
  } else if (hours > 12) {
    hours -= 12;
    ampm = 'pm';
  }

  return hours + ':' + minutes + ' ' + ampm;
}

document.write(convertTime('14:26:00'));