let array = new Array(10);

for (let i = 0; i < 7; i++) {
    array[i] = i + 1;
}

let beforeInsert = array.slice();
console.log("插入前数组：", beforeInsert);

for (let i = 6; i >= 2; i--) {
    array[i + 1] = array[i];
}
array[2] = 8;

let afterInsert = array.slice();
console.log("插入后数组：", afterInsert);