Productable: a tiny function to create product of arrays

productable.js

function Productable(arr) {
  const self = {
    array: arr.map(e => Array.isArray(e) ? e : [e]),
    product: (otherArr) => {
      const newArray = [];
      self.array.forEach(e => {
        otherArr.forEach(oe => {
          newArray.push([...e, oe]);
        });
      });
      return new Productable(newArray);
    },
    toArray: () => self.array
  };
  return self;
}

module.exports = {
  Productable
};