递归函数不以return语句结尾?

function findSolution(target) {
  function find(current, history) {
    if (current == target) {
      return history;
    } else if (current > target) {
      return null;
    } else {
      return find(current + 5, `(${history} + 5)`) ||
             find(current * 3, `(${history} * 3)`);
    }
  }
  return find(1, "1");
}

console.log(findSolution(24));
// → (((1 * 3) + 5) * 3)

最让我困惑的是,当当前目标时,如果我可以记录当前值,并且它多次超过目标值,但随后继续递归,尝试不同的组合,为什么函数不返回null&end?