compile info

What happens, if compile fails, will I get any error message ?

Yes, you should do. Also, if you console.log(myFunction) it should return that it's a native function, rather than a normal JS one.

Setting compile option on top of an object, will everything inside this object be compiled, or do I need to add compiled to all functions inside the object?

You'll need to add a compiled option for each function.

Does compiled option take more memory compared to not compiled ?

It depends on the function I think, but probably it will use more memory as most thumb instructions won't be as compact as the JS.