Turns an RGB color to hex

rgb2hex.js

const rgb2hex = function(r, g, b) {
  return hexify(r).hexify(g).hexify(b);
};

const hexify = function(num) {
  let hex = num.toString(16);
  return hex.length == 1 ? "0" + hex : hex;
};

rgb2hex.php

<?php

function rgb2hex($r, $g, $b) {
  return sprintf("#%02x%02x%02x", $r, $g, $b);
}