编辑代码

const arr = [2, 4, 7, 8, 9, 11, 45, 66, 69, 78];
const target = 12;

function searchTarget(arr, target) {
    let count = 1, start = 0, end = arr.length - 1;
    while (start <= end) {
        const middle = Math.floor((start + end) / 2);
        const result = arr[middle];
        console.log(count);
        if (result === target) {
            return middle;
        }
        if (result > target) {
            end = middle - 1;
        }
        if (result < target) {
            start = middle + 1;
        }
        count++;
    }
    return -1;
}
console.log(searchTarget(arr, target));