As a relative new kotliner I still find when to us...

# getting-started

[Henrik Johansson]

As a relative new kotliner I still find when to use Extension functions vs methods not easy. I mean they both work right and obvious cases with third party libs are easy. Is there any glaring down sides to extensoin functions other than tighter coupling? I have to import the functions at call site which I don't when using a method? I get there might be a tiny performance boost from the static dispatch but surely the compiler could do the same dispatch in many cases for methods as well?

[CLOVIS]

Downsides to extension functions: they cannot be inherited/overriden by children classes, so it's not possible for a child to provide a faster implementation

[CLOVIS]

On the JVM, the performance difference between static dispatch and dynamic dispatch is essentially irrelevant, unless you're doing something very specific you probably shouldn't take it into account

[CLOVIS]

Have you read this? If not, I recommend it → https://elizarov.medium.com/extension-oriented-design-13f4f27deaee

[Henrik Johansson]

Thx I will read it asap!

[Henrik Johansson]

The article makes sense and we will try to to internalize it in our team. It's sound advice.

[CLOVIS]

In case you didn't notice, the author is Roman Elizarov, the Project Lead for Kotlin. There's essentially no answer that's more authoritative than this 🙂 I highly recommend his blog posts in general, they're all very well written.

[Henrik Johansson]

I did notice 🙂 I got the idea but I would like even more description of the do's-and-dont's. I mean you learn as you make mistakes but it's always faster to learn from someone else's experience