JS powerset, got bored

powerset.js

function powerset(input) {
  let accum = [];

  // This loop which index in the array you begin pulling from
  for (let start = 0; start < input.length; ++start) {
    // This loop determines *how many* elements to add to your accumulator
    for (let baseLength = 1; start + baseLength <= input.length; ++baseLength) {
      const base = input.slice(start, start + baseLength);
      accum.push(base);
    }
  }

  accum.push([]);
  return accum;
}


function run(input) {
  console.log(`Powerset for ${JSON.stringify(input)} is ${JSON.stringify(powerset(input))}`);
}

const input1 = [1, 2, 3, 4, 5];
const input2 = [];
const input3 = [6, 6, 6];
const input4 = [7];

run(input1);
run(input2);
run(input3);
run(input4);

FWIW, it has bag semantics, so input3 will return many duplicate sets since it's all 6s.