JSFiddle - React, Tailwind, and code Playground

HTML

<p id='display'></p>

JavaScript

var nums = [0.0000, 0.0001, 1, 2.0, 3.0000, 4.00123];

function fn(num) {
  var int, dec;
  var num_str = String(num).split('.');
  int = parseInt(num_str[0]);
  dec = String(num_str[1] || 0);
  if (/^0+$/g.test(dec)) {
    dec = '0';
  }
  return [int, dec].join('.');
}

nums.forEach(function(n) {
  console.log(n, fn(n));
});