JavaScript filter method not giving unique result

Question

i am trying to filter the unique ones from a given array using filter method but its throwing an empty array, here is the code

function dual(a) {
  if (Array.isArray(a)) {
    let unique = a.filter((val, index) => {
      a.indexOf(val) == index
    })
    return unique;
  }
}
console.log(dual([3, 1, 1, 2, 2])) //expected result [3,1,2] but showing []

https://stackoverflow.com/a/70865229/12057512. `const no_dupes = [...new Set(arr)];` — Emil Karlsson, May 24 '22 at 08:44
Does this answer your question? [Curly Brackets in Arrow Functions](https://stackoverflow.com/questions/35440265/curly-brackets-in-arrow-functions) — Ivar, May 24 '22 at 08:49

score 2 · Answer 1 · answered May 24 '22 at 08:46

2

You may use Set() to create a unique array:

const arr = [3,1,1,2,2]

var uniqueArray = [...new Set(arr)]

console.log(uniqueArray)

answered May 24 '22 at 08:46

Rayl

188
1
8

score 1 · Answer 2 · answered May 24 '22 at 08:45

1

You are missing return statements from both your function and your filter array method.

answered May 24 '22 at 08:45

Jack

220
1
8

JavaScript filter method not giving unique result

2 Answers2