Question about prototypes in separate files

prototype.js

module.exports = function () {

    Room.prototype.findCreeps = function (role) {

        var creeps = room.find(FIND_MY_CREEPS);
        if (role && role != "") {
            creeps = _.filter(creeps, function (c) {
                return (c.memory.role == role);
            });
        }
        return creeps;
    };


};