How to handle platform specific assets?

Hello,

I am using Creator 3.4.2
I am coming from Cocos2dx C++ so best thing about 2dx C++ was we can easily add macros in source files and those files wont be added in final binary.
May i know what will be the similar way of doing the same in Creator?
Not macros but what else we can do to achieve same?
Any automation while generating build via Command line?
Lets say platform specific we wont to change few assets as well then?

Thanks.
Regards,
Smit