arr = [1,2,5,8,9,10,20,30,40] 有一个从小到大排序好的数组,现在输入一个数，要求按照原来的规律插入到数组中

var arr = [1, 2, 5, 8, 9, 10, 20, 30, 40];
    var num = 15;
    var left = 0, right = arr.length - 1;
    while (left <= right) {
        var mid = Math.floor((left + right) / 2);
        if (arr[mid] === num) {
            arr.splice(mid, 0, num); break;
        } else if (arr[mid] < num) {
            left = mid + 1;
        } else { right = mid - 1; }
    } if (left > right) {
        arr.splice(left, 0, num);
    }
    console.log(arr);