// generators are lazy so maxItems isn't needed anymore - you just take as many items as you need
// it's also lazy, so if you need less items you will pay less for it. Naming a Set `set` is like naming a Number `number`
const uniqueMergeWithoutMax = function *(arrays, withoutValue) {
  const seen = new Set();
  for(const array of arrays) {
    for(const item of array) {
      if (item === withoutValue || seen.has(item)) continue;
      seen.add(item);
      yield item;
    }
  }
};