Câu hỏi

function withVar() {
  const b = () => a;
  var a = 24;
  return b;
}

function withLet() {
  const b = () => a;
  let a = 24;
  return b;
}

function changingValue() {
  let a = 24;
  const b = () => a;
  a = 42;
  return b;
}

console.log(withVar()()); // ??
console.log(withLet()()); // ??
console.log(changingValue()()); // ??