Solution for Thinkful's Express routing course (https://projects.thinkful.com/express-routing-for-safe-travel-99/)

routing.js

/*

  Traveling app for Thinkful's Express routing course
  To run:
  ```sh
  npm init
  npm install express
  npm install node-emoji
  node routing.js
  ```

 */

var express = require('express');
var emoji = require('node-emoji');
var travelMap = [
    [" ", " ", " ", " ", " "],
    ["e", "g", " ", " ", "g"],                                                  
    [" ", "g", " ", " ", " "],
    [" ", " ", " ", "s", " "],
    [" ", " ", "g", " ", "g"]
];
var port = process.env.PORT || 8000;


// Create the app
// ------------------

var app = express()
var router = express.Router({
  mergeParams: true
})


// Add the routes
// ------------------

router.get('/plot', function (request, response) {

  // Create the path
  var path = request.params[0].
      split('').
      map(function (direction) {
        return {
          n: 'north',
          w: 'west',
          s: 'south',
          e: 'east'
        }[direction]
      }).
      join(', then ');

  response.send('You plan to travel ' + path + '.');
});

router.get('/travel', function (request, response) {
  // Calculate the initial position
  var currentX;
  var currentY;
  var maxX = (travelMap[0] || []).length - 1;
  var maxY = (travelMap || []).length - 1;
  travelMap.map(function (row, yIndex) {
    sIndex = row.indexOf('s');
    if (sIndex > -1) {
      currentX = sIndex;
      currentY = yIndex;
    }
  });

  // Calculate the journey
  request.params[0].
    split('').
    map(function (direction) {
      var change = {
        n: {x: 0, y: -1},
        w: {x: -1, y: 0},
        s: {x: 0, y: 1},
        e: {x: 1, y: 0}
      }[direction]

      currentX += change.x;
      currentY += change.y;

      if (currentY < 0 || currentY > maxY || currentX < 0 || currentX > maxX) {
        response.send('You fell off a cliff.');
      }

      if (travelMap[currentY][currentX].toLowerCase() === 'g') {
        response.send(
          'You walked straight into a grue and were devoured. ' +
          'It was...Grue-some');
      }
    });

  if (travelMap[currentY][currentX].toLowerCase() === 'e') {
    response.send(
      emoji.emojify('You maaaaaaaaadeee iiiit! :information_desk_person:'));
  }

  response.send("You haven't been eaten...yet.");
});


// Only match on valid journey routes
app.use(/\/([nwse]+)/, router);


// Start the app
app.listen(port, function () {
  console.log('App running on port ' + port);
});