JS: Implementation of Cartesian product

cartesian.js

const cartesian = (...arrays) => arrays.reduce((cartesianPart, array) => (
    [].concat(...
      cartesianPart.map(cartesianPartTuple =>
        array.map(it => cartesianPartTuple.concat(it))
      )
    )
  ), [[]]);


console.log(cartesian([1,2], [3,4], [5,6]))