app.js

var express = require('express');
var path = require('path');

var index = require('./routes/index');

var app = express();

if(!process.env.API_KEY){
  console.log('Set the Openweather API key as an environment variable named API_KEY');
  process.exit(-1);
}
app.set('view engine', 'jade');

app.use('/', index);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;