Get unique values from an array

var array = [1,2,3,4,1,2,1];

array.filter((x,i,a) => a.indexOf(x) == i);

// --result is as below

[1, 2, 3, 4];

filter method is explained as below
x--> the item in array
i--> the index of item
a--> the array itself

Looking for much shorter script? :-)

[... new Set(array)]

This gives the same result
[1, 2, 3, 4]