Summary
When writing code, you can call any function as long as it’s public, and similarly, you Can access any object’S public properties or methods. Usually, access to code is all or none – a piece of code can be either public or private. However, there are cases when more fine-grained controls could be useful.
Take a simple backend application with three layers: routes > controllers > services. Each layer has its own directory, and each file in a directory houses a module.
A look at a list of the most popular apps in the world. The list includes Facebook, Twitter, Google, Microsoft and others. The most popular app is Google Play.
