[Algorithm] Powerset Problem

By given an array [1,2,3]:

Return all possible combinations. for example: [[], [1], [2], [3], [1, 2].... [1,2,3]]

function combination(ary) {
  let result = new Set();
  function helper(ary, idx, path = [], result) {
    if (idx === ary.length) {
      return result.add(path);
    }

    let path_inc_current = [...path, ary[idx]];
    let path_not_inc_current = [...path];

    helper(ary, idx + , path_inc_current, result);
    helper(ary, idx + , path_not_inc_current, result);
  }

  helper(ary, , [], result);
  return Array.from(result);
}

console.log(JSON.stringify(combination([, , ]))); // [[1,2,3],[1,2],[1,3],[1],[2,3],[2],[3],[]]