How to implement validation check?

Question

React

I have an input field and a button, I work with a server and use Redux to load data from the server. I enter the text and send it to the server. The text must have a certain form. I have a question about how validation works in React using Redux and Express. Do processing on the React side and write additional actions and reducer before sending the data? Do you have examples or articles? Optional only with Express.
An example is a registration form: login verification, etc. Here's how to work with this? How is everything arranged?

Answer 1

In general, it is necessary to check both on the client and on the server. As an example, you can see validation on the server here and validation on the client here , it is quite well described there.