03. Add and Remove Elements

function solve(arr) {
  const result = [];

  arr.forEach((_, index) => {
    if (arr[index] === 'add') {
      result[index] = index + 1;
    } else if (arr[index] === 'remove') {
      result.pop();
    }
  });

  if (result.length <= 0) {
    console.log('Empty');
  }

  result.map((el) => el !== undefined && console.log(el));
}