如何使用JS求數(shù)組差集的方法

arr1 = [1,2,3,4];
arr2 = [1,2,3]; 
 subSet = set2 = subset = (!

 alpha = [1, 2, 3, 4= [1，2，3= $.merge($.grep(a, $.inArray(i, b) == -1 $.inArray(i, a) == -1&& console.log( $.arrayIntersect(alpha, beta) );
//結(jié)果等于4

var subSet = function(arr1, arr2) { 
var set1 = new Set(arr1); 
var set2 = new Set(arr2); 
var subset = []; 
for (let item of set1) { 
if (!set2.has(item)) {
 subset.push(item);
 }
 } return subset;
};