getConstraints

A helper that returns an object containing the validation attributes for each field by introspecting the zod schema.

1import { getConstraints } from '@conform-to/zod/v3/future';
2// or
3import { getConstraints } from '@conform-to/zod/v4/future';
4
5const constraint = getConstraints(schema);

#Parameters

`schema`

The value to introspect. If it's not a valid zod schema, the function returns undefined.

#Examples

Deriving constraints from a schema

1import { getConstraints } from '@conform-to/zod/v3/future';
2// or
3// import { getConstraints } from '@conform-to/zod/v4/future';
4import { z } from 'zod';
5
6const schema = z.object({
7  title: z.string().min(5).max(20),
8  description: z.string().min(100).max(1000).optional(),
9  password: z
10    .string()
11    .regex(/[A-Z]/, 'Must contain an uppercase letter')
12    .regex(/[0-9]/, 'Must contain a number'),
13});
14const constraint = getConstraints(schema);
15// {
16//   title: { required: true, minLength: 5, maxLength: 20 },
17//   description: { required: false, minLength: 100, maxLength: 1000 },
18//   password: {
19//     required: true,
20//     pattern: '^(?=.*(?:[A-Z]))(?=.*(?:[0-9])).*$',
21//   },
22// }

Passing constraints to useForm

Call getConstraints directly and pass the result to useForm to enable native HTML validation attributes (e.g. required, minLength, min, pattern) on your form fields:

1import { useForm } from '@conform-to/react/future';
2import { getConstraints } from '@conform-to/zod/v3/future';
3
4const { form, fields } = useForm({
5  constraint: getConstraints(schema),
6});

Using with configureForms

Pass getConstraints to configureForms to automatically derive constraints for all forms without repeating it in every useForm call:

1import { configureForms } from '@conform-to/react/future';
2import { getConstraints } from '@conform-to/zod/v3/future';
3
4const { useForm } = configureForms({
5  getConstraints,
6});

#Tips

Pattern limitations

The pattern generation is best-effort with the following limitations:

Regex flags: The i (case-insensitive) flag is not supported. No pattern is generated for case-insensitive regexes or when the serialized regex is not a valid HTML pattern under the browser's v flag.
Backreferences: Numbered backreferences (\1, \2, etc.) may break when multiple regex validators for the same field are combined into one pattern. Named backreferences (\k<name>) are more reliable, but each regex combined into the same pattern must use unique group names.