createCounter = function(init) {
    let count = init;

    increment = () => ++count;

    decrement = () => --count;

    reset = () => {
      count = init;
      return count;
    }

    return {
      increment,
      decrement, 
      reset
    }
}
@param {integer} init
@return { increment: Function, decrement: Function, reset: Function }