Notes

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');

var app = express(); // app represents the express server

// view engine setup
app.set('views', path.join(__dirname, 'views')); //
app.set('view engine', 'pug');

app.use(logger('dev')); //use morgan for logging
app.use(express.json()); // return the data in json format
app.use(express.urlencoded({ extended: false })); // return the data in protected format
app.use(cookieParser()); // use cookies in my application
app.use(express.static(path.join(__dirname, 'public'))); // the static files are in the public folder

app.use('/', indexRouter); //localhost:3000/
app.use('/users', usersRouter);

//Error Handling Blocks
// catch 404 and forward to error handler
app.use(function(req, res, next) {
next(createError(404));
});

// 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;