我只是想知道我在javascript中添加2个数组的代码出了什么问题

const array1 = [1, 2, 3];
const array2 = [4, 5, 6];
const combinedArray = array1.concat(array2);
console.log(combinedArray);

[1, 2, 3, 4, 5, 6]

const array1 = [1, 2, 3];
const array2 = [4, 5, 6];
const combinedArray = [...array1, ...array2];
console.log(combinedArray);

[1, 2, 3, 4, 5, 6]