❗️Что будет на выходе:

function tag(strings, ...values) {
  return strings.reduce((acc, str, i) => {
    return acc + str + (values[i] ? values[i].toUpperCase() : '');
  }, '');
}

const first = "hello";
const second = "world";

const result = tag`${first} and ${second} are great!`;

console.log(result);

Ответ: HELLO and WORLD are great!

JavaScript test | #JavaScript