javascript get intersection of two arrays

1let intersection = arrA.filter(x => arrB.includes(x));

1function getArraysIntersection(a1,a2){
2    return  a1.filter(function(n) { return a2.indexOf(n) !== -1;});
3}
4var colors1 = ["red","blue","green"];
5var colors2 = ["red","yellow","blue"];
6var intersectingColors=getArraysIntersection(colors1, colors2); //["red", "blue"]
7
8

1// Generic helper function that can be used for the three operations:        
2const operation = (list1, list2, isUnion = false) =>
3    list1.filter(
4        (set => a => isUnion === set.has(a.userId))(new Set(list2.map(b => b.userId)))
5    );
6
7// Following functions are to be used:
8const inBoth = (list1, list2) => operation(list1, list2, true),
9      inFirstOnly = operation,
10      inSecondOnly = (list1, list2) => inFirstOnly(list2, list1);
11
12// Sample data
13const list1 = [
14    { userId: 1234, userName: 'XYZ'  }, 
15    { userId: 1235, userName: 'ABC'  }, 
16    { userId: 1236, userName: 'IJKL' },
17    { userId: 1237, userName: 'WXYZ' }, 
18    { userId: 1238, userName: 'LMNO' }
19];
20const list2 = [
21    { userId: 1235, userName: 'ABC'  },  
22    { userId: 1236, userName: 'IJKL' },
23    { userId: 1252, userName: 'AAAA' }
24];
25  
26console.log('inBoth:', inBoth(list1, list2)); 
27console.log('inFirstOnly:', inFirstOnly(list1, list2)); 
28console.log('inSecondOnly:', inSecondOnly(list1, list2));