Big O in JS: The basic that you need to know, see more at: https://medium.com/p/a5abb45570fa

printItemAndNextO1.js

const printItemAndNextItem = (...items) =>
  items.forEach(
    (item, index) => items[index + 1] && console.log(item, items[index + 1]),
  );

/* will return: 
  1 2
  2 3
  3 4
  */

printItemAndNextItem(1, 2, 3, 4);