30-seconds-of-code/snippets/unique-values-of-array.md

Unique values of array

use ES6 Set and the ...rest operator to discard all duplicated values.

const unique = c => [...new Set(c)]
// unique([1,2,2,3,4,4,5]) -> [1,2,3,4,5]

Use Array.filter for an array containing only the unique values

const unique = c => c.filter(i => c.indexOf(i) === c.lastIndexOf(i))
// unique([1,2,2,3,4,4,5]) -> [1,3,5]