mantine-form

name

mantine-form

description

Build forms using @mantine/form in the mantine-9 repository. Use this skill when: (1) setting up a form with useForm, (2) adding validation rules or async validation, (3) working with nested object or array fields, (4) sharing form state across components with createFormContext, (5) using uncontrolled mode for performance, (6) using the standalone useField hook, or (7) any task involving useForm, getInputProps, onSubmit, insertListItem, or form validation.

Mantine Form Skill

Core Workflow

1. Set up the form

const form = useForm({
  mode: 'controlled',       // or 'uncontrolled' for large forms
  initialValues: {
    email: '',
    age: 0,
  },
  validate: {
    email: isEmail('Invalid email'),
    age: isInRange({ min: 18 }, 'Must be at least 18'),
  },
});

2. Wire inputs with getInputProps

<TextInput {...form.getInputProps('email')} label="Email" />
<NumberInput {...form.getInputProps('age')} label="Age" />

For checkboxes pass { type: 'checkbox' }:

<Checkbox {...form.getInputProps('agreed', { type: 'checkbox' })} label="I agree" />

3. Handle submission

<form onSubmit={form.onSubmit((values) => console.log(values))}>
  ...
  <Button type="submit">Submit</Button>
</form>

onSubmit only calls the handler when validation passes. To handle failures:

form.onSubmit(
  (values) => save(values),
  (errors) => console.log('Validation failed', errors)
)

Validation

Rules object (most common)

validate: {
  name: isNotEmpty('Required'),
  email: isEmail('Invalid email'),
  password: hasLength({ min: 8 }, 'Min 8 chars'),
  confirmPassword: matchesField('password', 'Passwords do not match'),
}

Function (for cross-field logic)

validate: (values) => ({
  endDate: values.endDate < values.startDate ? 'End must be after start' : null,
})

When to validate

validateInputOnChange: true,        // validate all fields on every change
validateInputOnChange: ['email'],    // validate specific fields only
validateInputOnBlur: true,          // validate on blur instead

Modes

Mode	State storage	Re-renders	Input props
'controlled' (default)	React state	On every change	value + onChange
'uncontrolled'	Refs	None	defaultValue + onChange

In uncontrolled mode, use form.key('fieldPath') as the React key prop when you need to force a re-render of an input.

References

• references/api.md — Full API: useForm options, complete return value, useField, createFormContext, createFormActions, all built-in validators, key types
• references/patterns.md — Code examples: nested objects, array fields, async validation, form context across components, transformValues, useField standalone