Migrating from 2.x to 3.x

Removed

• res.render() "status" option (use res.statusCode=)
• res.render() "charset" option (use res.charset=)
• app.dynamicHelpers() (use app.locals.use(callback))
• app.helpers() (use app.locals)
• the concept of a "layout" (template engine specific now)
• partial() (template engine specific)
• res.partial()
• "view options" setting, use app.locals
• "hints" setting
• req.isXMLHttpRequest (use req.xhr)
• app.error() (use middleware with (err, req, res, next))

Changed

• res.send(body[, code]) is now res.send([code,] body)
• res.redirect(url[, code]) is now res.redirect([code,] url)
• res.json(obj[, code]) is now res.json([code,] obj)
• renamed app.register() to app.engine()

Template engine integration

.. todo

View system changes

By removing the concept of a "layout" & partials in Express 3.x template engines will have greater control over file I/O. This means integration with template engines much easier, and greatly simplify the view system's internals.

This also enables template engines to supply their own means of inheritance, for example later releases of Jade provide Django-inspired template inheritance, where the view being rendering specifies the layout it wants to extend.

Error handling middleware

.. todo

App- & Request-level local variables

.. todo