如何生成包含两个数组的副本？

const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];
const arrCopy = arr1.concat(arr2);
console.log(arrCopy);

const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];
const arrCopy = [...arr1, ...arr2];
console.log(arrCopy);

const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];
const arrCopy = arr1.slice(0).concat(arr2.slice(0));
console.log(arrCopy);