App Engine

Register the given template engine callback as ext

By default will require() the engine based on the file extension. For example if you try to render a "foo.jade" file Express will invoke the following internally, and cache the require() on subsequent calls to increase performance.

app.engine('jade', require('jade').__express)

For engines that do not provide .__express out of the box - or if you wish to "map" a different extension to the template engine you may use this method. For example mapping the EJS template engine to ".html" files:

app.engine('html', require('ejs').renderFile)

In this case EJS provides a .renderFile() method with the same signature that Express expects: (path, options, callback), though note that it aliases this method as ejs.__express internally so if you're using ".ejs" extensions you dont need to do anything.

Some template engines do not follow this convention, the <a href="https://github.com/visionmedia/consolidate.js">consolidate.js</a> library was created to map all of node's popular template engines to follow this convention, thus allowing them to work seemlessly within Express.

var engines = require('consolidate')
app.engine('haml', engines.haml)
app.engine('html', engines.hogan)