JavaScript for循环返回未定义

function findNumber(numbers, target) {
  for (let i = 0; i < numbers.length; i++) {
    if (numbers[i] === target) {
      return i;  // 返回目标值的索引
    }
  }
}

const numbers = [1, 2, 3, 4, 5];
const target = 6;
const result = findNumber(numbers, target);

console.log(result);  // 输出：undefined

function findNumber(numbers, target) {
  for (let i = 0; i < numbers.length; i++) {
    if (numbers[i] === target) {
      return i;  // 返回目标值的索引
    }
  }
  
  return -1;  // 目标值不存在，返回-1
}

const numbers = [1, 2, 3, 4, 5];
const target = 6;
const result = findNumber(numbers, target);

console.log(result);  // 输出：-1