How much knowledge you should know to be able to say that "I know this programming language" on your resume or CV? for cpp, js

as much knowledge as it takes YOU to feel comfortable with putting it on your resume.

At least 4 months

at least one qualified rant abt it

I'd argue it depends on how common the tech is and if there's a likelyhood someone would imagine you can work with it and if you'd be able to based on overall experience.

It's fine to list Pascal and Prolog even if you just took a few classes on them during your first college year and forgot all about them, cause no one is gonna hire you to work on those.

But when it comes to modern tech, be careful.

When it comes to C/C++ people expect you to know malloc and pointers by heart. But in reality: if you're just a webdev applying for React jobs - no one is gonna make you do a bit of C on the side. So no harm in listing them even if you forgot.

If you're a JS dev and you worked with every JS framework under the sun it's fine to list some old one you forgot about like BackboneJS cause you could easily re-learn it. But if you haven't touched JS in years... don't list that JS framework!

@tosensei he's actually correct
But if you don't have professional experience you need to find a way to explain this

If they ask
Which they might not

Being able to demonstrate idiomatic usage of the language or tech.

ie: Don't think you know Python while still programming like you did in C++.

@Demolishun Agree. If one writes python syntax in a .cpp file it's a red flag.

But I think it's fine if someone admits "Been a while since I wrote C++ so I can't remember the syntax for including header files off the top of my head. I know I have to reference my_class.h just can't remember the keyword."

Well considering a lot of devs just put shit they have never touched before on their resume and lie blatantly, I feel like an exaggeration of skill is not too bad if you feel like you could learn it fast.

If it's on your resume, I can ask you to build thing "X" in said language and expect you to do it.

Now, the job title will affect the quality or even scope of X but you get the jist of it.