series
SOLID Principles
Code that looked fine — until it wasn't. That's where each principle begins.
Parts4
Open Closed Principle (OCP): Extend Without BreakingCode that has to be opened every time requirements change is code you will eventually break. Learn how OCP lets new behavior arrive as new files, not as edits to existing ones.6 min read
Liskov Substitution Principle (LSP): Keep the PromiseA subtype that can't fully honor its parent's contract doesn't announce itself — it waits. Learn how LSP ensures the contract you depend on is the contract you actually get.4 min read
Dependency Inversion Principle (DIP): Depend on AbstractionsWhen business logic knows which database it's talking to, the database owns the business logic. Learn how DIP breaks that grip by making policy depend on what it needs, not on how it's delivered.8 min read
Interface Segregation Principle (ISP): Narrow the ContractA shared contract that grows to serve everyone ends up serving no one well. Learn how ISP keeps each interface honest about what its client actually needs.8 min read