How to cancel page refresh when adding data to database using json-server?

Question

React

React app.
When starting in useEffect(), I make a request to json-server `y, having received a response, I add it to state. In the child component, I make a post request. When changes are made, the application restarts.
what to do, how to be? thanks in advance) e.preventDefault() doesn't save

Answer 1

Not very clear :)
How to understand the application is restarting?
Show the code, it's better to post it somewhere)