Question 1

How to validate a form with Yup in React?

Accepted Answer

Define a Yup schema matching your form fields, then use validate or validateSync in your form handler—integrate with state libraries like Formik or React Hook Form. Yup's async support works well with React's async rendering for server validation.

Question 2

Yup vs Zod: which is better for TypeScript?

Accepted Answer

Yup excels with deep TypeScript inference and runtime transformations, while Zod is often favored for its simpler API and faster performance in pure validation. Choose Yup if you need extensive casting and async features, but Zod for minimal bundle size.

Question 3

How to add custom validation rules in Yup?

Accepted Answer

Use the .test() method to define custom validation functions with error messages, or extend schema types globally with addMethod for reusable methods, as detailed in the README's test and extensibility sections.

Question 4

Does Yup support conditional validation based on other fields?

Accepted Answer

Yes, use the .when() method to create conditional schemas dependent on sibling or context values, allowing for complex logic like dynamic min/max limits, with examples provided for object and array schemas.

Question 5

How to handle i18n for error messages in Yup?

Accepted Answer

Configure setLocale with functions that return translation keys and values, then integrate with libraries like i18next. The README shows how to generate error objects for dynamic localization in validation errors.

Question 6

Can Yup validate nested arrays and objects?

Accepted Answer

Yes, Yup supports nested structures with array().of() and object().shape(), and you can validate specific paths using validateAt. The reach function helps access inner schemas for dynamic validation.

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