[How to] Oracle database connection?

Hello, I am trying to connect to an Oracle database to get some data I could use for my scripted test cases (javascript). Is there any tutorial/documentation on how to achieve this? I have searched but only found posts of 10+ years ago, and some links posted there are already gone. 

I'd really appreciate if someone could give me a hint or some examples on how to connect to an oracle DB. 

Thanks.