get unique item from two different array in javascript

Question

I have two arrays

var a = [4,8,9,7];
var b = [1,5,7,3,9];

I want result

 [4,8,1,5,3]

I have tried using filter-

function diffArray(arr1, arr2) {
var newArr = [];
var newArr2 = [];
newArr = arr1.filter(function(e) {
  return arr2.indexOf(e) < 0;
});

newArr2 = arr2.filter(function(e) {
  return arr1.indexOf(e) < 0;
});
var arr = newArr.concat(newArr2);
 return arr;
}

Is there any better way to get the same result.

Possible duplicate of How to merge two arrays in JavaScript and de-duplicate items — Bùi Đức Khánh
– Bùi Đức Khánh, Commented Nov 25, 2017 at 10:57
So you want the symmetric difference? Loop over both arrays, assign the array values as keys to an object with the value 1, if the key already exists, set the value to 0, then take only the keys that have value 1 (with Object.entries and filter). — Sebastian Simon
– Sebastian Simon, Commented Nov 25, 2017 at 10:57
@KhánhBùiĐức No, this is not about the symmetric difference required here. — Sebastian Simon
– Sebastian Simon, Commented Nov 25, 2017 at 10:59

Nina Scholz · Accepted Answer · 2017-11-25 10:59:33Z

3

You could check the index and last index of the item and filter only if the index is the same.

var a = [4, 8, 9, 7],
    b = [1, 5, 7, 3, 9],
    unique = a.concat(b).filter((v, _, a) => a.indexOf(v) === a.lastIndexOf(v));
    
console.log(unique);

answered Nov 25, 2017 at 10:59

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Mritunjay Upadhyay · Accepted Answer · 2017-11-25 11:00:39Z

1

I can do like this.

var a = [4, 8, 9, 7];
var b = [1, 5, 7, 3, 9];
var c = b.reduce((r, o) => {
if (r.indexOf(o) !== -1) {
    r.splice(r.indexOf(o), 1);
} else {
 r.push(o);
}
 return r;
}, a);
console.log(c);

answered Nov 25, 2017 at 11:00

Mritunjay Upadhyay

1,0941 gold badge17 silver badges28 bronze badges

2 Comments

Sebastian Simon Over a year ago

But why is this better?

Mritunjay Upadhyay Over a year ago

No Sir, Nina Scholz's answer is best. You can check it out

Collectives™ on Stack Overflow

get unique item from two different array in javascript

2 Answers 2

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related