Test Driven Development

Why use TDD?

• It forces you to think
• It makes debugging easier
• It makes coding more fun

Basic steps of TDD

• Red: Write a test and make sure it fails.
• Green: Write the simplest, easiest possible code to make the test pass.
• Refactor: Optimise and/or simplify the application code, making sure that all the tests still pass.

TDD encourages you to

• Write tests
• Write smaller, easier to understand portions of code

The module wrapper

• Before a module's code is executed, Node.js will wrap it with a function wrapper.

(function(exports, require, module, __filename, __dirname) { // Module code actually lives in here });

• It keeps top-level variables (such as var, const or let) scoped to the module rather than the global object.
• It helps to provide some global-looking variables that are actually specific to the module, such as:
• The module and exports objects that the implementor can use to export values from the module.
• The convenience variables __filename and __dirname, containing the module's absolute filename and directory path.