questions.js

function fn(number) {
  return parseInt(number.toString(2).split('').reverse().join(''), 2);
}

// 1000 -> 0001 (8 -> 1)
console.log('fn(8)', fn(8) === 1);
// 1100 -> 0011 (12 -> 3)
console.log('fn(12)', fn(12) === 3);
// 1110 -> 0111 (14 -> 7)
console.log('fn(14)', fn(14) === 7);
// 1111 -> 1111 (15 -> 15)
console.log('fn(15)', fn(15) === 15);

// --------------------------------------------------------------------

/* Code #1 */

/* Code #2 */ setTimeout(() => alert('Hello, Code #2'), 1000);

/* Code #3 */

// --------------------------------------------------------------------