Notes on Express

May 17, 2015


In express the order in which routes and middleware are added is significant

Express can distinguish between the 404 and 500 handlers by the number of arguments their callback functions take.

Express handles the urls in comparison to nodejs.

Views can use different engines

  • jade (express3-handlebars package)
  • handlebars (based on the popular language-independent templating language Mustache)

Best practices

The first time you do something correctly, it may take five times as long to do it as it would have to do it quick and dirty. The second time, though, it’s only going to take three times as long. By the time you’ve done it correctly a dozen times, you’ll be doing it almost as fast as the quick and dirty way.

  • documentation
  • attribution
  • experimentation

Quality Assurance

  • reach
  • functionality
  • usability
  • aesthetics


  • page testing
  • cross-page testing
  • logic testing
  • linting
  • link checking

nodemon and grunt plugin

Page testing

Embed tests in the page itself.

#save it in the package.json, only dev environment
npm install --save-dev mocha
#save it in the package.json
npm install --save mocha

chai assertion library

Request object

  • req.params
  • req.param(name)
  • req.query
  • req.body
  • req.route
  • req.cookies/req.signedCookies
  • req.headers
  • req.accepts([types])
  • req.ip
  • req.path
  • req.xhr
  • req.protocol
  • req.url/req.originalUrl
  • req.acceptedLanguages

Response object

  • res.status(code)
  • res.set(name,value)
  • res.cookie(name,value, [options], res.clearCookie(name,[options]))
  • res.redirect([status],url)
  • res.send(body),res.send(status,body)
  • res.json(json),res.json(status,json)
  • res.jsonp(json),res.jsonp(status,json)
  • res.type(type)
  • res.format(object)
  • res.attachment([filename]),,[filename],[callback])
  • res.sendFile(path,[options],[callback])
  • res.links(links)
  • res.locals,res.rendr(view,[locals],callback)

Firstcheck the Express API documentation, then Express source, finally Node documentation

  • lib/application.js
  • lib/express.js
  • lib/request.js
  • lib/response.js
  • lib/router/route.js

Rendering content

  • res.send //test page
  • res.render //content
  • req.query, req.session, req.cookie/req.signedCookies
app.get('/greeting', function(req, res){ res.render('about', {
                message: 'welcome',
                userid: req.cookie.userid,
                username: req.session.username,
}); });

Other pages and concepts

  • themeforest
  • wrapbootstrap
  • Express scaffolding utility
  • handlebars
  • html5 boilerplate
  • Ayi‐ ma’s Redirect Path
  • middleware
  • mailing
  • nodemailer