TODO

Used to have this as default on charkeys but that seemed like a questionable default

it('should group keys with same first letter by array', ()=> {
  const input = {
    xylophone: 1,
    xonkey: 2,
    xebra: 3,
    zebra: 4
  };
  const output = somethingsomething(input);
  Assert.deepEqual(output, {x: [1, 2, 3], z: 4});
});