apps/mantine.dev/src/pages/form/use-form.mdx
import { FormDemos } from '@docs/demos'; import { Layout } from '@/layout'; import { MDX_DATA } from '@/mdx';
export default Layout(MDX_DATA.useForm);
The @mantine/form package does not depend on any other libraries. You can use it with or without @mantine/core inputs:
All examples below use the following example use-form hook.
import { useForm } from '@mantine/form';
const form = useForm({
mode: 'uncontrolled',
initialValues: {
path: '',
path2: '',
user: {
firstName: 'John',
lastName: 'Doe',
},
fruits: [
{ name: 'Banana', available: true },
{ name: 'Orange', available: false },
],
accepted: false,
},
});
// get the current form values
form.getValues();
// Set all form values
form.setValues(values);
// Set all form values using the previous state
form.setValues((prev) => ({ ...prev, ...values }));
// Set the value of a single field
form.setFieldValue('path', value);
// Set the value of a nested field
form.setFieldValue('user.firstName', 'Jane');
// Resets form values to `initialValues`,
// clears all validation errors,
// resets touched and dirty state
form.reset();
// Reset the field at `path` to its initial value
form.resetField('path');
// Sets initial values, used when the form is reset
form.setInitialValues({ values: 'object' });
// Inserts the given list item at the specified path
form.insertListItem('fruits', { name: 'Apple', available: true });
// An optional index may be provided to specify the position in a nested field.
// If the index is provided, the item will be inserted at the given position.
// If the index is larger than the current list, the element is inserted at the last position.
form.insertListItem('fruits', { name: 'Orange', available: true }, 1);
// Removes the list item at the specified path and index.
form.removeListItem('fruits', 1);
// Replaces the list item at the specified path and index with the given item.
form.replaceListItem('fruits', 1, { name: 'Apple', available: true });
// Swaps two items of the list at the specified path.
// You should make sure that there are elements at the `from` and `to` index.
form.reorderListItem('fruits', { from: 1, to: 0 });
import { useForm } from '@mantine/form';
const form = useForm({
mode: 'uncontrolled',
initialValues: {
email: '',
user: {
firstName: '',
lastName: '',
},
},
validate: {
email: (value) => (value.length < 2 ? 'Invalid email' : null),
user: {
firstName: (value) =>
value.length < 2
? 'First name must have at least 2 letters'
: null,
},
},
});
// Validates all fields with the specified `validate` function or schema, sets form.errors
await form.validate();
// Validates a single field at the specified path, sets form.errors
await form.validateField('user.firstName');
// Works the same way as form.validate but does not set form.errors, returns Promise<boolean>
await form.isValid();
await form.isValid('user.firstName');
// true while any async validation is running
form.validating;
// true while async validation is running for a specific field
form.isValidating('email');
Validation errors occur when defined validation rules were violated, initialErrors were specified in useForm properties,
or validation errors were set manually.
// get the current errors state
form.errors;
// Set all errors
form.setErrors({ path: 'Error message', path2: 'Another error' });
// Set an error message at the specified path
form.setFieldError('user.lastName', 'No special characters allowed');
// Clears all errors
form.clearErrors();
// Clears the error of the field at the specified path
form.clearFieldError('path');
Wrapper function for the form onSubmit and onReset event handler. The onSubmit handler accepts as a second argument a function
that will be called with the errors object when validation fails.
import { useForm } from '@mantine/form';
function Demo() {
const form = useForm({ mode: 'uncontrolled' });
const handleSubmit = (values: typeof form.values) => {
console.log(values);
};
return (
<>
<form onSubmit={form.onSubmit(handleSubmit)} />
<form
onSubmit={form.onSubmit(
(values, event) => {
console.log(
values, // <- form.getValues() at the moment of submit
event // <- form element submit event
);
},
(validationErrors, values, event) => {
console.log(
validationErrors, // <- form.errors at the moment of submit
values, // <- form.getValues() at the moment of submit
event // <- form element submit event
);
}
)}
/>
<form onReset={form.onReset}></form>
</>
);
}
By default, event.preventDefault() is called on the form onSubmit handler.
If you want to change this behavior, you can pass the onSubmitPreventDefault option
to the useForm hook. It can have the following values:
always (default) - always call event.preventDefault()never - never call event.preventDefault()validation-failed - call event.preventDefault() only if validation failedimport { useForm } from '@mantine/form';
const form = useForm({
mode: 'uncontrolled',
onSubmitPreventDefault: 'never',
});
// Returns true if the user interacted with any field inside the form in any way
form.isTouched();
// Returns true if the user interacted with the field at the specified path
form.isTouched('path');
// Set all touched values
form.setTouched({ 'user.firstName': true, 'user.lastName': false });
// Clears the touched status of all fields
form.resetTouched();
// Returns true if form values are not deep equal to initialValues
form.isDirty();
// Returns true if the field value is not deep equal to initialValues
form.isDirty('path');
// Sets the dirty status of all fields
form.setDirty({ 'user.firstName': true, 'user.lastName': false });
// Clears the dirty status of all fields, saves form.values snapshot
// After form.resetDirty is called, form.isDirty will compare
// form.getValues() to the snapshot instead of initialValues
form.resetDirty();
UseFormReturnType can be used when you want to pass the form as a prop to another component:
import { TextInput } from '@mantine/core';
import { useForm, UseFormReturnType } from '@mantine/form';
interface FormValues {
name: string;
occupation: string;
}
function NameInput({
form,
}: {
form: UseFormReturnType<FormValues>;
}) {
return (
<TextInput
key={form.key('name')}
{...form.getInputProps('name')}
/>
);
}
function OccupationInput({
form,
}: {
form: UseFormReturnType<FormValues>;
}) {
return (
<TextInput
key={form.key('occupation')}
{...form.getInputProps('occupation')}
/>
);
}
function Demo() {
const form = useForm<FormValues>({
mode: 'uncontrolled',
initialValues: { name: '', occupation: '' },
});
return (
<>
<NameInput form={form} />
<OccupationInput form={form} />
</>
);
}