How to get unique values in an array

Question

How can I get a list of unique values in an array? Do I always have to use a second array or is there something similar to java\'s hashmap in JavaScript?

I am going

Answer 1

Here's a much cleaner solution for ES6 that I see isn't included here. It uses the Set and the spread operator: ...

var a = [1, 1, 2];

[... new Set(a)]

Which returns [1, 2]