const PowerSet = array => array.reduce((accumalator, current) => accumalator.concat(accumalator.map(n => [current].concat(n))), [[]]);
console.log(PowerSet([1,2]))
const PowerSet = array => array.reduce((accumalator, current) => accumalator.concat(accumalator.map(n => [current].concat(n))), [[]]);
console.log(PowerSet([1,2]))