I am currently working on the project YouTubeLayer. The prototype worked fine initially, but when I tried to move it to a working production system and scale it, everything started breaking. It felt like playing Jenga — touch one block, and the whole tower comes crashing down.
That’s when I stumbled upon something that completely changed the way I thought about software design — the SOLID principles.
These five principles aren’t just fancy theory; they’re a way of writing code that’s easy to understand, extend, and maintain. And trust me — once you start applying them, your code (and your sanity) will thank you.
Let’s go through them one by one, in the simplest way possible 👇
Definition:
A class should have only one reason to change — in other words, it should do only one thing.
In plain English:
Don’t make a “God class” that does everything — logging, sending emails, calculating bills, and making coffee.
Example:
I once worked on a UserManager class that handled both user authentication and sending email notifications. Every time we updated the notification logic — like changing email templates or adding a new notification type — the authentication system mysteriously broke. 😅
We eventually split it into two separate classes — AuthManager for authentication and NotificationManager for sending emails. After that, changes became smooth and predictable. It was such a relief!
Why it matters:
It makes debugging, testing, and updating code simpler and safer.
Definition:
Classes should be open for extension but closed for modification.
In plain English: