What can I do next after completing mern stack

Question

Please suggest some that I can do to get strong grip

MongoDB
Express
Node
React

Answer 1

Do you mean to learn them or to practise?
The first:
You can search resources like w3 or wherever else you like.
The second:
Ask yourself or some friends and family for an idea of something that could be useful online and then try to code it.

Answer 2

https://sololearn.com/compiler-playground/c8jzVECTOh2r/?ref=app