Liskov Substitution Principle Explained - SOLID Design Principles

Writing clean code is tough, and is one of the largest differences between junior and senior developers. One way that you can quickly improve your code and start writing well designed code now is to implement the Liskov substitution principle. This principle is part of the SOLID design principles and is, in my opinion, the most important rule of SOLID for object oriented programming.

The main idea of the Liskov substitution principle is that any function/module that interacts with a class should also be able to interact with all subclasses of that class without breaking. This essentially means that a class is interchangeable with its subclasses.

Most likely you have written tons of code in violation of this principle, I know I have, but hopefully this video will help introduce you to why this principle is so good at making your code clean and maintainable.

🧠 Concepts Covered:

- What the Liskov substitution principle is
- Why the Liskov substitution principle is important
- How to use the Liskov substitution principle
- How to spot violations of the Liskov substitution principle

🌎 Find Me Here:

#SOLID #WDS #LiskovSubstituionPriniciple

[MrPogi-lfgz]

Yes to composition vs inheritance video!

[majicboca]

Kyle, your approach to explaining these abstract, seemingly obscure principles and concepts with simple examples, is brilliant. So instead of approaching dry and abstract concepts from the top down with professorial lectures of principles that need to be understood, your bottom up approach with spot-on examples illuminate the subject matter. I have noticed how your subscriber base has been deservedly growing, and it is because of your clarity in presenting these topics and the relatively short videos that make it digestible. I wish you much continued success and look forward to your new videos. Best always.

[fernandobalino]

I didn’t realize you could be a great programmer, a fantastic teacher, AND a supermodel at the same time. Great video.

[rapha]

Uauh. I've programmed since 2000s (vb6, turbo Pascal, etc) and I still enjoy each one of your videos! Good job!

[muhammadumair]

You are such a great instructor ! Finally I understand all about SOLID in just couple of minutes.

[SkriptKid]

You are the dom perignon of online JS educators. Clear, concise and well structured! Thanks very much for your content 🙌🏻

[rishabhkalra]

Okay... This is probably the first time i understood liskov. Thanks a lot man and yea i think you should make videos on composition and aggregation too...

Overall your content for solid is pretty solid 🎉👌

[maharun]

Thanks a bunch. Found your video while searching about "Why is it not allowed to narrow down scope of a method while overriding?" and also why the developers choose to do so.

It makes sense now. Thanks for making these topics so easy to understand.

[reactdejv]

I love these SOLID principles series, nicely done man!

[jackhaugh]

I've read the whole clean code book by Uncle Bob and still didn't understand these SOLID principles as much as until your 10 minute video. Thanks!

[bishopshawiii]

Finally a simple explanation of the solid principles....👍 for composition vs. Inheritance

[phogbinh]

Thank you for simplifying the Liskov principle for all of us with easy-to-comprehend examples. Keep up the good work!

[archiee]

The best content for SOLID on the Internet.

[puspamadak]

I had never understood the concepts of OOP in my school classes. Your explanations are very easy to understand!

[mj]

This is an interview question I used to ask devs.. Btw, between square inherits rect or rect inherits square, always inherit rect from square, as you are adding a paramater, a second size dimension. Square has sideLength. Rectangle has a second sid legnth. Things get a lot cleaner following that.

[shayama]

These expalmes are everywhere, really programmers cannot find more intresting expalmes...

[MrPauld]

Thank you. As an amateur coder you have taught me tons. Thank you. Love your videos.

[Shinbo]

Hands down best coding channel on YouTube. Many thanks and keep em coming!

[desarrollojava]

And another very clear, clever and successful teaching video. Thank you!

[davivify]

Sounds like polymorphism to me. I've used polymorism twice to very good avail. Once in an undo/redo (stack based) system and once in a linked list of tokens. And all I can say is Thank God for it. And one thing I love about it is how it allows for future expansion. If I should add new token types or undo/redo types on the future, no sweat. I don't have to change a thing in either my containers or my base classes. I could even distribute the code as a library and never worry about users needing to change the base code.