by-the-power-set-of-castle-grayskull.md

By the Power Set of Castle Grayskull ^{5 Kyu}

^{LINK TO THE KATA - MATHEMATICS ALGORITHMS}

Description

Write a function that returns all of the sublists of a list/array.

Example:

power([1,2,3]);=>[[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]]

For more details regarding this, see the power set entry in wikipedia.

Solution

const power = array => {
  let results = [[]]
  for (let i = 0; i < array.length; i++) {
    let len = results.length
    for (let j = 0; j < len; j++) {
      results.push([...results[j], array[i]])
    }
  }
  return results
}