5. Interface Segregation Principle Explained | SOLID Principles in JavaScript & Node.js

In this video, we explain the Interface Segregation Principle (ISP) — the “I” in SOLID principles — using simple JavaScript and Node.js examples. If you are a beginner in JavaScript, Node.js, or software design, this video is for you. We start from the basics, explain what ISP means in simple words, show bad code that violates ISP, and then refactor the same example into clean, ISP-compliant code. Since JavaScript does not have interfaces like Java or C#, we demonstrate how to apply ISP using classes, composition, and small service contracts in real-world Node.js applications. 🔹 What you will learn in this video: • What is Interface Segregation Principle (ISP) • Why fat interfaces are bad • How ISP improves code maintainability • ISP violation example in JavaScript • Refactoring code to follow ISP • Applying ISP in real Node.js projects • Clean coding practices for backend developers This video is part of the SOLID Principles series for JavaScript and Node.js developers. 👉 Perfect for: • JavaScript beginners • Node.js backend developers • Interview preparation • Clean code & system design learners Github Link: https://github.com/leelanarasimha Instagram: https://www.instagram.com/leelawebdev/ Telegram: http://t.me/LeelaWebDev Facebook Page: https://www.facebook.com/LeelaWebDev Twitter Page: https://twitter.com/leelanarsimha Linkedin: https://www.linkedin.com/in/leela-narasimha-reddy-86517948/ GitHub: https://github.com/leelanarasimha Youtube Page: https://www.youtube.com/leelawebdev If you like my video, please subscribe to my channel. My Playlists: React Complete Course: https://www.youtube.com/watch?v=LMFAaNWmKII&list=PL_euSNU_eLbfuahgrm63xLCWfpl2MaTAr Vue Complete Course: https://www.youtube.com/watch?v=x0uc670hw_8&list=PL_euSNU_eLbedoBv-RllKj_f2Yh--91nZ Angular NGRX Complete Course: https://www.youtube.com/watch?v=3WI5BEXVkmE&list=PL_euSNU_eLbdg0gKbR8zmVJb4xLgHR7BX Angular Complete Course: https://www.youtube.com/watch?v=wI18jE_LHME&list=PL_euSNU_eLbeAJxvVdJn5lhPWX9IWHhxs TypeScript Complete Course: https://www.youtube.com/watch?v=xns0Vaip4wc&list=PL_euSNU_eLbfJEwuNa43lM89yfev537Mj ES6 Complete Course: https://www.youtube.com/watch?v=tt1SkTpHUUU&list=PL_euSNU_eLbfIr88Sgtalv4W58mTW07V4 Javascript Complete Course: https://www.youtube.com/watch?v=JZmwaniKUUc&list=PL_euSNU_eLbeHPrIcllJ1_9hdcffwGuWi GIT Complete Course: https://www.youtube.com/watch?v=vMdSqMf6BPY&list=PL_euSNU_eLbegnt7aR8I1gXfLhKZbxnYX ESLint Complete Course: https://www.youtube.com/watch?v=OYrIfgi_Ghg&list=PL_euSNU_eLbeVd_eDmWzUpEmXizWQRmEm RxJS Complete Course: https://www.youtube.com/watch?v=Q-iZ1JHA0GE&list=PL_euSNU_eLbc0HclFbirIaMXaXzQJ_K4n Declarative Reactive Programming in Angular Complete Course: https://www.youtube.com/watch?v=P38auPts2vs&list=PL_euSNU_eLberdNLX5idpheqHLjdZltJy Angular CLI Complete Course Tutorial: https://www.youtube.com/watch?v=iEPegoPPHDk&list=PL_euSNU_eLbfmSwZYA3ab3a3JGQk8pQdZ Angular UnitTesting Complete Course: https://www.youtube.com/watch?v=VnaDJOucT-4&list=PL_euSNU_eLbcqJ6_Z3FOZJ8mLZ2oMFItV My Courses Playlist Page: https://www.youtube.com/c/LeelaWebDev/playlists #leelawebdev Join this channel to get access to perks: https://www.youtube.com/channel/UC1J-YH25LCjvLnFjy7WDqGA/join