How to check username and password format?

I am using formik to build forms in React Native and Yup is the default validation package for formik.

In the app that I am building, it requires users to put in their email, password, and username. Yup’s email validation works well, but is there a way to do the standard password and username validation? For example, the username shouldn’t include any whitespace.

> const validationSchema = Yup.object().shape({
> email: Yup.string().required().email().label("Email"),
> password: Yup.string().required().min(4).label("Password"),
> username: Yup.string().required().min(5).label("User name"),
> });

[jquense]

yup doesn’t have any special rules for user names or passwords, since they differ wildy depending on use case. You should break up each of their validation requirements into single things like “minimum 8 chars” or “no whitespace” and look for builtin methods that allow that. In general most things can be implemented with one or more matches test, which accepts a regular expression. If you aren’t comfortable with regex’s you can also implement the logc via a custom test (using test())

[jquense]

Whiles users might find the google checks adequate that doesn’t make it a helpful default to include unfortunately. Ultimately the yup schema needs to match whatever the backend server implements, which varies wildly depending on use case and product choices. On the other hand implementing what you need in yup should be straightforward and simple once you learn the basics of the library. I do agree that the docs could be reworked to better highlight how to customize behavior