Express Clone

This project is a copy of express.js. I made it so that I could better understand the source code of express.js. Writing the code in this repository helped me understand ...

1. How to test APIs using supertest
2. How to write a .d.ts file for javascript libraries that don't have types
3. How to test javascript library code by using npm link
4. How express handles app.method and app.use function calls
5. How callback functions work
6. How to create classes using functions
7. The mixin pattern (multiple inheritance)
8. Default exports