zod-validation-expert

Define a Zod schema, infer its type with z.infer, and pass it to useForm via zodResolver from @hookform/resolvers/zod. Validation errors then map automatically to formState.errors for display next to each input.

parse throws a ZodError on invalid input and requires try/catch, while safeParse returns a result object with a success flag. safeParse is preferred because TypeScript narrows the result type, enabling clean error handling without exceptions.

Define a schema describing each variable, using z.coerce.number() for ports and z.enum for NODE_ENV, then call schema.parse(process.env) at startup. The app fails immediately if any variable is missing or invalid, and the result is fully typed.

The .optional() modifier permits undefined, not empty strings. To treat an empty string as absent, use .or(z.literal("")) or preprocess with a transform that converts empty strings to undefined before validation.

Use .refine on the object schema comparing data.password and data.confirmPassword, and set the path option to ["confirmPassword"]. Without the path option, the error will not attach to the correct form field.

This error occurs with deeply recursive schemas. Use z.lazy(() => NodeSchema) for self-referential structures and define the recursive TypeScript type explicitly instead of relying solely on z.infer.