closuredemo

A very minimal JS code for teaching about closures

Software needed

Node.js from http://nodejs.org/ or installed by your favourite package manager.

Usage

node server.js

Fetch the file with a browser: http://localhost:3000/demo.html

Teaching

File: demo.html

The point is to show how the req variable is usable even if it is executed only after the network request returns.

To stress the point it may be handy to make the server code slower with e.g. setTimeout function. (Which incidentally can teach more about closures.)

Another demonstration is to make the req object null after the req.send(null) function call.