在数组中查找最接近的较小数字

function findClosestSmallerNumber(arr, target) {
  let closestSmaller = -Infinity;

  for (let i = 0; i < arr.length; i++) {
    if (arr[i] < target && arr[i] > closestSmaller) {
      closestSmaller = arr[i];
    }
  }

  return closestSmaller;
}

// 示例用法
const array = [1, 5, 9, 12, 15];
const targetNumber = 10;
const closestSmallerNumber = findClosestSmallerNumber(array, targetNumber);
console.log(closestSmallerNumber);  // 输出 9