Version 5.6.0

import { useState } from 'react';
import { useFavicon } from '@mantine/hooks';
import { Group, Button } from '@mantine/core';

function Demo() {
  const [favicon, setFavicon] = useState('https://mantine.dev/favicon.svg');
  const setTwitterFavicon = () => setFavicon('https://twitter.com/favicon.ico');
  const setMantineFavicon = () => setFavicon('https://mantine.dev/favicon.svg');

  useFavicon(favicon);

  return (
    <Group position="center">
      <Button onClick={setTwitterFavicon}>Twitter favicon</Button>
      <Button onClick={setMantineFavicon}>Mantine favicon</Button>
    </Group>
  );
}

import { useForm, FORM_INDEX } from '@mantine/form';
import { NumberInput, TextInput, Button } from '@mantine/core';

function Demo() {
  const form = useForm({
    validateInputOnChange: [
      'email',
      'name',
      // use FORM_INDEX to reference fields indices
      `jobs.${FORM_INDEX}.title`,
    ],
    initialValues: { name: '', email: '', age: 0, jobs: [{ title: '' }, { title: '' }] },

    // functions will be used to validate values at corresponding key
    validate: {
      name: (value) => (value.length < 2 ? 'Name must have at least 2 letters' : null),
      email: (value) => (/^\S+@\S+$/.test(value) ? null : 'Invalid email'),
      age: (value) => (value < 18 ? 'You must be at least 18 to register' : null),
      jobs: {
        title: (value) => (value.length < 2 ? 'Job must have at least 2 letters' : null),
      },
    },
  });

  return (
    <form style={{ maxWidth: 320, margin: 'auto' }} onSubmit={form.onSubmit(console.log)}>
      <TextInput label="Name" placeholder="Name" {...form.getInputProps('name')} />
      <TextInput mt="sm" label="Email" placeholder="Email" {...form.getInputProps('email')} />
      <NumberInput
        mt="sm"
        label="Age"
        placeholder="Age"
        min={0}
        max={99}
        {...form.getInputProps('age')}
      />
      <TextInput
        mt="sm"
        label="Job 1"
        placeholder="Job 1"
        {...form.getInputProps('jobs.0.title')}
      />
      <TextInput
        mt="sm"
        label="Job 2"
        placeholder="Job 2"
        {...form.getInputProps('jobs.1.title')}
      />
      <Button type="submit" mt="sm">
        Submit
      </Button>
    </form>
  );
}

import { useState } from 'react';
import { useForm } from '@mantine/form';
import { TextInput, Button, Box, Code } from '@mantine/core';

function Demo() {
  const [submittedValues, setSubmittedValues] = useState('');

  const form = useForm({
    initialValues: {
      firstName: 'Jane',
      lastName: 'Doe',
      age: '33',
    },

    transformValues: (values) => ({
      fullName: `${values.firstName} ${values.lastName}`,
      age: Number(values.age) || 0,
    }),
  });

  return (
    <Box sx={{ maxWidth: 400 }} mx="auto">
      <form
        onSubmit={form.onSubmit((values) => setSubmittedValues(JSON.stringify(values, null, 2)))}
      >
        <TextInput
          label="First name"
          placeholder="First name"
          {...form.getInputProps('firstName')}
        />
        <TextInput
          label="Last name"
          placeholder="Last name"
          mt="md"
          {...form.getInputProps('lastName')}
        />
        <TextInput
          type="number"
          label="Age"
          placeholder="Age"
          mt="md"
          {...form.getInputProps('age')}
        />
        <Button type="submit" mt="md">
          Submit
        </Button>
      </form>

      {submittedValues && <Code block>{submittedValues}</Code>}
    </Box>
  );
}