How to find all subsets of a set in JavaScript? (Powerset of array)

Question

I need to get all possible subsets of an array.

Say I have this:

[1, 2, 3]

How do I get this?

[], [1], [2], [3], [1, 2], [2, 3], [1, 3], [1, 2, 3]

I am interested in all subsets. For subsets of specific length, refer to the following questions:

• Finding subsets of size n: 1, 2
• Finding subsets of size > 1: 1

Answer 1

Here is one more very elegant solution with no loops or recursion, only using the map and reduce array native functions.

const getAllSubsets = 
      theArray => theArray.reduce(
        (subsets, value) => subsets.concat(
         subsets.map(set => [value,...set])
        ),
        [[]]
      );

console.log(getAllSubsets([1,2,3]));