S - Single Responsibility Principle
A module, class or function should do one primary thing and nothing else.O - Open/Closed Principle
Modules, classes and functions should be open for extension but closed for modification. The initial functionality should not be changed but may be extended via composition or inheritance.L - Liskov Substitution Principle
A subclass should have "is a" relationship with the base class. Wherever you can use a base class, you should be able to use a derived class.I - Interface Segregation Principle
Minimize the number of methods in a given interface. Instead, expose multiple smaller interfaces. Clients can choose to implement just the interfaces they require.D - Dependency Inversion Principle (DIP)
High level modules should not depend on lower level modules. Constructors for higher level modules should accept abstractions (interfaces) of lower level modules. At runtime, Dependency Container injects a concrete instance of the abstraction into the constructor.Additional Resources
https://www.digitalocean.com/community/conceptual_articles/s-o-l-i-d-the-first-five-principles-of-object-oriented-design
