let arr1 = ["1","2","3"]
let arr2 = ["6","1","2","3"]

如上代码所示，比较arr1和arr2，并取出这个"6"，这样子的代码该怎么写呢

在这里先谢谢各位大神们的解答了，小弟感激不尽！

JS取出两个数组中的不同或相同元素

const arr1 = ["1","2","3"];
const arr2 = ["6","1","2","3"];
const result = arr1.concat(arr2).filter((value, index, arr) => {
   return  arr.indexOf(value) === arr.lastIndexOf(value);
});
console.log(result); // ["6"]