javascript - Removing duplicate array values and then storing them [react]

Question

I'm trying to strip the duplicate array values from my current array. And I'd like to store the fresh list (list without duplicates) into a new variable.

var names = ["Daniel","Lucas","Gwen","Henry","Jasper","Lucas","Daniel"];

const uniqueNames = [];
const namesArr = names.filter((val, id) => {
    names.indexOf(val) == id;  // this just returns true
});

How can I remove the duplicated names and place the non-duplicates into a new variable?

ie: uniqueNames would return...

["Daniel","Lucas","Gwen","Henry","Jasper"] 

(I'm using react jsx) Thank you!

Answer 1

You can do it in a one-liner

const uniqueNames = Array.from(new Set(names));

// it will return a collection of unique items

Note that @Wild Widow pointed out one of your mistake - you did not use the return statement. (it sucks when we forget, but it happens!)

I will add to that that you code could be simplified and the callback could be more reusable if you take into account the third argument of the filter(a,b,c) function - where c is the array being traversed. With that said you could refactor your code as follow:

const uniqueNames = names.filter((val, id, array) => {
   return array.indexOf(val) == id;  
});

Also, you won't even need a return statement if you use es6

const uniqueNames = names.filter((val,id,array) => array.indexOf(val) == id);