30-seconds-of-code/snippets/powerset.md

Powerset

Use reduce() combined with map() to iterate over elements and combine into an array containing all combinations.

const powerset = arr =>
  arr.reduce( (a,v) => a.concat(a.map( r => [v].concat(r) )), [[]]);
// powerset([1,2]) -> [[], [1], [2], [2,1]]