old_contents: const logger = require('heroku-logger');
  const Router = require('express-promise-router');
  
  const db = require('../db');
  
  // create a new express-promise-router
  // this has the same API as the normal express router except
  // it allows you to use async functions as route handlers
  const router = new Router();
  
  // export our router to be mounted by the parent application
  module.exports = {
      router: router,
      getEndOfMonth: getEndOfMonth,
      getNextDate: getNextDate,
      getEventsByDay: getEventsByDay,
      getEventsByMonth: getEventsByMonth,
  };
  
  router.use('/:year/:month/:day', getEventsByDay);
  
  router.use('/:year/:month', getEventsByMonth);
  
  function getEventsByDay(request, response) {
      setCorsHeaders(response);
  
      const year = request.params.year;
      const month = request.params.month;
      const day = request.params.day;
      const date = year + '/' + month + '/' + day;
      const nextDate = getNextDate(year, month, day);
      const sql = "SELECT * FROM events WHERE (start_date BETWEEN '" + date + "' AND '" + nextDate + "') OR (end_date BETWEEN '" + date + "' AND '" + nextDate + "') OR ('" + date + "' BETWEEN start_date AND end_date);";
  
      logger.info("Requested Day: " + date);
      logger.info("SQL: " + sql);
      db.query(sql).then((rows) => {response.send(rows)});
  }
  
  function getEventsByMonth(request, response) {
      setCorsHeaders(response);
  
      const year = request.params.year;
      const month = request.params.month;
      const date = year + '/' + month + '/01';
      const endOfMonth = getEndOfMonth(year, month);
      const sql = "SELECT * FROM events WHERE (start_date BETWEEN '" + date + "' AND '" + endOfMonth + "') OR (end_date BETWEEN '" + date + "' AND '" + endOfMonth + "') OR ('" + date + "' BETWEEN start_date AND end_date);";
  
      logger.info("Requested Month: " + date);
      logger.info("SQL: " + sql);
      db.query(sql).then((rows) => {response.send(rows)});
  }
  
  function setCorsHeaders(response) {
      response.header("Access-Control-Allow-Origin", "*");
      response.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  
      return response;
  }
  
  function getEndOfMonth(year, month) {
      const end = new Date(year, month, 0);
  
      return end.getFullYear() + '/' + (end.getMonth() + 1) +'/' +end.getDate();
  }
  
  function getNextDate(year, month, day) {
      let monthIndex = parseInt(month) - 1;
  
      let nextDay = new Date(year, monthIndex, (parseInt(day) + 1));
  
      return nextDay.getFullYear() + '/' + (nextDay.getMonth() + 1) + '/' + nextDay.getDate();
  }
  
new_contents: const logger = require('heroku-logger');
  const Router = require('express-promise-router');
  
  const db = require('../db');
  
  // create a new express-promise-router
  // this has the same API as the normal express router except
  // it allows you to use async functions as route handlers
  const router = new Router();
  
  // export our router to be mounted by the parent application
  module.exports = {
      router: router,
      getEndOfMonth: getEndOfMonth,
      getNextDate: getNextDate,
      getEventsByDay: getEventsByDay,
      getEventsByMonth: getEventsByMonth,
  };
  
  router.use('/:year/:month/:day', async (req, res) => {getEventsByDay(req, res)});
  
  router.use('/:year/:month', async (req, res) => {getEventsByMonth(req, res)});
  
  function getEventsByDay(request, response) {
      setCorsHeaders(response);
  
      const year = request.params.year;
      const month = request.params.month;
      const day = request.params.day;
      const date = year + '/' + month + '/' + day;
      const nextDate = getNextDate(year, month, day);
      const sql = "SELECT * FROM events WHERE (start_date BETWEEN '" + date + "' AND '" + nextDate + "') OR (end_date BETWEEN '" + date + "' AND '" + nextDate + "') OR ('" + date + "' BETWEEN start_date AND end_date);";
  
      logger.info("Requested Day: " + date);
      logger.info("SQL: " + sql);
      db.query(sql).then((rows) => {response.send(rows)});
  }
  
  function getEventsByMonth(request, response) {
      setCorsHeaders(response);
  
      const year = request.params.year;
      const month = request.params.month;
      const date = year + '/' + month + '/01';
      const endOfMonth = getEndOfMonth(year, month);
      const sql = "SELECT * FROM events WHERE (start_date BETWEEN '" + date + "' AND '" + endOfMonth + "') OR (end_date BETWEEN '" + date + "' AND '" + endOfMonth + "') OR ('" + date + "' BETWEEN start_date AND end_date);";
  
      logger.info("Requested Month: " + date);
      logger.info("SQL: " + sql);
      db.query(sql).then((rows) => {response.send(rows)});
  }
  
  function setCorsHeaders(response) {
      response.header("Access-Control-Allow-Origin", "*");
      response.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  
      return response;
  }
  
  function getEndOfMonth(year, month) {
      const end = new Date(year, month, 0);
  
      return end.getFullYear() + '/' + (end.getMonth() + 1) +'/' +end.getDate();
  }
  
  function getNextDate(year, month, day) {
      let monthIndex = parseInt(month) - 1;
  
      let nextDay = new Date(year, monthIndex, (parseInt(day) + 1));
  
      return nextDay.getFullYear() + '/' + (nextDay.getMonth() + 1) + '/' + nextDay.getDate();
  }
  
subject: Fix to Router.use() requires a middleware function but got a Object