perenstrom

export const isValidLuhn = (input) => {
  if (!/^\d+$/.test(input)) {
    return false;
  }

  const arr = input
    .split('')
    .reverse()
    .map((x) => parseInt(x, 10));
  const lastDigit = arr.splice(0, 1)[0];

perenstrom

<!-- 
  Source set to choose differently sized images depending on device
  This is a scenario where large screens have a 500px wide image,
  medium screens a 350px wide image, and small screens a 250px wide
  image. It is then up to the browser to select the correct image
  based on pixel density (1000w image for the 500px container if on
  a 2x retina display, for example).

  https://codepen.io/perenstrom/pen/JjbMvMa
-->

perenstrom

<?php

// Define variables
$dbuser 	= 'user';
$dbpassword 	= 'pass';
$dbname 	= 'dbname';
$hostname 	= 'host';
$port 		= 8889;

// Open database connection