TanStack Form

https://tanstack.com/form/latest/docs
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TanStack Form is a powerful and flexible form management library designed to simplify form state,...
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### Run Remix Development Server

Source: https://tanstack.com/form/latest/docs/framework/react/examples/remix

Starts the local development server for the Remix application.

```shellscript
npm run dev
```

--------------------------------

### Build and Run Remix for Production

Source: https://tanstack.com/form/latest/docs/framework/react/examples/remix

Commands to build the application for production and start the production server.

```sh
npm run build
```

```sh
npm start
```

--------------------------------

### Install TanStack Devtools and Form Plugin

Source: https://tanstack.com/form/latest/docs/framework/react/guides/devtools.md

Installs the necessary TanStack Devtools and the specific plugin for TanStack Form using npm. These are essential for enabling the devtools functionality.

```bash
npm i @tanstack/react-devtools
npm i @tanstack/react-form-devtools
```

--------------------------------

### Use useStore hook

Source: https://tanstack.com/form/latest/docs/framework/react/reference/variables/useStore.md

Example of selecting a count value from a counter store.

```tsx
const count = useStore(counterStore, (state) => state.count)
```

--------------------------------

### TanStack Start Form Integration

Source: https://tanstack.com/form/latest/docs/framework/react/examples/tanstack-start

Demonstrates a route component using useForm with server-side state merging and form field validation.

```typescript
import { createFileRoute } from '@tanstack/react-router'
import { mergeForm, useForm, useTransform } from '@tanstack/react-form-start'
import { useStore } from '@tanstack/react-store'
import { getFormDataFromServer, handleForm } from 'src/utils/form'
import { formOpts } from 'src/utils/form-isomorphic'

export const Route = createFileRoute('/')({
  component: Home,
  loader: async () => ({
    state: await getFormDataFromServer(),
  }),
})

function Home() {
  const { state } = Route.useLoaderData()

  const form = useForm({
    ...formOpts,
    transform: useTransform((baseForm) => mergeForm(baseForm, state), [state]),
  })

  const formErrors = useStore(form.store, (formState) => formState.errors)

  return (
    <form action={handleForm.url} method="post" encType={'multipart/form-data'}>
      {formErrors.map((error) => (
        <p key={error as never as string}>{error}</p>
      ))}

      <form.Field
        name="age"
        validators={{
          onChange: ({ value }) =>
            value < 8 ? 'Client validation: You must be at least 8' : undefined,
        }}
      >
        {(field) => {
          return (
            <div>
              <input
                name="age"
                type="number"
                value={field.state.value}
                onChange={(e) => field.handleChange(e.target.valueAsNumber)}
              />
              {field.state.meta.errors.map((error) => (
                <p key={error as string}>{error}</p>
              ))}
            </div>
          )
        }}
      </form.Field>
      <form.Subscribe
        selector={(formState) => [formState.canSubmit, formState.isSubmitting]}
      >
        {([canSubmit, isSubmitting]) => (
          <button type="submit" disabled={!canSubmit}>
            {isSubmitting ? '...' : 'Submit'}
          </button>
        )}
      </form.Subscribe>
    </form>
  )
}
```

--------------------------------

### Complete Array Form Implementation

Source: https://tanstack.com/form/latest/docs/framework/react/guides/arrays.md

A comprehensive example showing a full form with array management, submission handling, and subscription for button state updates.

```jsx
function App() {
  const form = useForm({
    defaultValues: { people: [] },
    onSubmit({ value }) { alert(JSON.stringify(value)) },
  })

  return (
    <form onSubmit={(e) => { e.preventDefault(); e.stopPropagation(); form.handleSubmit() }}>
      <form.Field name="people" mode="array">
        {(field) => (
          <div>
            {field.state.value.map((_, i) => (
              <form.Field key={i} name={`people[${i}].name`}>
                {(subField) => (
                  <input value={subField.state.value} onChange={(e) => subField.handleChange(e.target.value)} />
                )}
              </form.Field>
            ))}
            <button onClick={() => field.pushValue({ name: '', age: 0 })} type="button">Add person</button>
          </div>
        )}
      </form.Field>
      <form.Subscribe selector={(state) => [state.canSubmit, state.isSubmitting]}>
        {([canSubmit, isSubmitting]) => <button type="submit" disabled={!canSubmit}>{isSubmitting ? '...' : 'Submit'}</button>}
      </form.Subscribe>
    </form>
  )
}
```

--------------------------------

### Integrating TanStack Form with Query

Source: https://tanstack.com/form/latest/docs/framework/react/examples/query-integration

A complete example showing form initialization with query data, handling mutations, and invalidating queries upon submission.

```typescript
import * as React from 'react'
import { createRoot } from 'react-dom/client'

import { TanStackDevtools } from '@tanstack/react-devtools'
import { formDevtoolsPlugin } from '@tanstack/react-form-devtools'
import { useForm } from '@tanstack/react-form'
import {
  QueryClient,
  QueryClientProvider,
  useMutation,
  useQuery,
} from '@tanstack/react-query'

import type { AnyFieldApi } from '@tanstack/react-form'

function FieldInfo({ field }: { field: AnyFieldApi }) {
  return (
    <>
      {field.state.meta.isTouched && !field.state.meta.isValid ? (
        <em>{field.state.meta.errors.join(',')}</em>
      ) : null}
      {field.state.meta.isValidating ? 'Validating...' : null}
    </>
  )
}

class DB {
  private data: { firstName: string; lastName: string }

  constructor() {
    this.data = { firstName: 'FirstName', lastName: 'LastName' }
  }

  getData(): { firstName: string; lastName: string } {
    return { ...this.data }
  }

  async saveUser(value: { firstName: string; lastName: string }) {
    this.data = value
    return value
  }
}

// Dummy Database to emulate server-side actions
const db = new DB()

export default function App() {
  const { data, isLoading, refetch } = useQuery({
    queryKey: ['data'],
    queryFn: async () => {
      await new Promise((resolve) => setTimeout(resolve, 1000))
      return db.getData()
    },
  })

  const saveUserMutation = useMutation({
    mutationFn: async (value: { firstName: string; lastName: string }) => {
      await new Promise((resolve) => setTimeout(resolve, 1000))
      db.saveUser(value)
    },
  })

  const form = useForm({
    defaultValues: {
      firstName: data?.firstName ?? '',
      lastName: data?.lastName ?? '',
    },
    onSubmit: async ({ formApi, value }) => {
      // Do something with form data
      await saveUserMutation.mutateAsync(value)

      // Invalidating query to recheck fresh data
      await refetch()

      // Reset the form to start-over with a clean state
      formApi.reset()
    },
  })

  if (isLoading) return <p>Loading..</p>

  return (
    <div>
      <h1>Simple Form Example</h1>
      <form
        onSubmit={(e) => {
          e.preventDefault()
          e.stopPropagation()
          form.handleSubmit()
        }}
      >
        <div>
          {/* A type-safe field component*/}
          <form.Field
            name="firstName"
            validators={{
              onChange: ({ value }) =>
                !value
                  ? 'A first name is required'
                  : value.length < 3
                    ? 'First name must be at least 3 characters'
                    : undefined,
              onChangeAsyncDebounceMs: 500,
              onChangeAsync: async ({ value }) => {
                await new Promise((resolve) => setTimeout(resolve, 1000))
                return (
                  value.includes('error') && 'No "error" allowed in first name'
                )
              },
            }}
            children={(field) => {
              // Avoid hasty abstractions. Render props are great!
              return (
                <>
                  <label htmlFor={field.name}>First Name:</label>
                  <input
                    id={field.name}
                    name={field.name}
                    value={field.state.value}
                    onBlur={field.handleBlur}
                    onChange={(e) => field.handleChange(e.target.value)}
                  />
                  <FieldInfo field={field} />
                </>
              )
            }}
          />
        </div>
        <div>
          <form.Field
            name="lastName"
            children={(field) => (
              <>
                <label htmlFor={field.name}>Last Name:</label>
                <input
                  id={field.name}
                  name={field.name}
                  value={field.state.value}
                  onBlur={field.handleBlur}
                  onChange={(e) => field.handleChange(e.target.value)}
                />
                <FieldInfo field={field} />
              </>
            )}
          />
        </div>
        <form.Subscribe
          selector={(state) => [state.canSubmit, state.isSubmitting]}
          children={([canSubmit, isSubmitting]) => (
            <>
              <button type="submit" disabled={!canSubmit}>
                {isSubmitting ? '...' : 'Submit'}
              </button>
              <button type="reset" onClick={() => form.reset()}>
                Reset
              </button>
            </>
          )}
        />
      </form>
    </div>
  )
}

const rootElement = document.getElementById('root')!

const queryClient = new QueryClient()

createRoot(rootElement).render(
  <React.StrictMode>
    <QueryClientProvider client={queryClient}>
      <App />
    </QueryClientProvider>

    <TanStackDevtools
      config={{ hideUntilHover: true }}
      plugins={[formDevtoolsPlugin()]}
    />
  </React.StrictMode>,
)
```

--------------------------------

### mount

Source: https://tanstack.com/form/latest/docs/reference/classes/FormGroupApi.md

Mounts the form group, typically used for initial setup and event listener attachment.

```APIDOC
## mount()

### Description
Mounts the form group, typically used for initial setup and event listener attachment.

### Method
`mount(): () => void;`

### Returns
- `() => void` - A function to unmount the form group and clean up resources.
```

--------------------------------

### onMount

Source: https://tanstack.com/form/latest/docs/reference/interfaces/FieldValidators.md

An optional function that runs on the mount event of an input. It can be used for initial validation or setup.

```APIDOC
## onMount

### Description
An optional function that runs when a field is mounted. This can be used for initial validation or setup tasks.

### Signature
```ts
optional onMount: RejectPromiseValidator<TOnMount>;
```
```

--------------------------------

### Basic TanStackDevtools Integration in React

Source: https://tanstack.com/form/latest/docs/framework/react/guides/devtools.md

Demonstrates the basic setup for integrating TanStackDevtools into a React application's root component. It shows how to import and render the component to enable basic devtools.

```tsx
import { TanStackDevtools } from '@tanstack/react-devtools'

import App from './App'

createRoot(document.getElementById('root')!).render(
  <StrictMode>
    <App />

    <TanStackDevtools />
  </StrictMode>,
)
```

--------------------------------

### TanStack Query Integration Setup

Source: https://tanstack.com/form/latest/docs/framework/react/examples/query-integration

Basic implementation of a form component that utilizes TanStack Query for data management.

```tsx
/src/index.tsx
```

--------------------------------

### Handle environment import errors

Source: https://tanstack.com/form/latest/docs/framework/react/guides/ssr.md

Example of the error message encountered when importing client-side hooks into server-side code.

```typescript
x You're importing a component that needs `useState`. This React hook only works in a client component. To fix, mark the file (or its parent) with the "use client" directive.
```

--------------------------------

### Implement Dynamic Validation with onDynamic

Source: https://tanstack.com/form/latest/docs/framework/react/guides/dynamic-validation.md

Demonstrates the basic setup of dynamic validation by providing an onDynamic function to the validators object and enabling it via revalidateLogic.

```tsx
import { revalidateLogic, useForm } from '@tanstack/react-form'

const form = useForm({
  defaultValues: {
    firstName: '',
    lastName: '',
  },
  validationLogic: revalidateLogic(),
  validators: {
    onDynamic: ({ value }) => {
      if (!value.firstName) {
        return { firstName: 'A first name is required' }
      }
      return undefined
    },
  },
})
```

--------------------------------

### getInfo

Source: https://tanstack.com/form/latest/docs/reference/classes/FormGroupApi.md

Gets the field information object for the current form group.

```APIDOC
## getInfo()

### Description
Gets the field information object for the current form group.

### Method
`getInfo(): FieldInfo<TParentData>;`

### Returns
- `FieldInfo<TParentData>` - The field information object.
```

--------------------------------

### Get Field Information

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldApi.md

Retrieves the field information object.

```ts
getInfo(): FieldInfo<TParentData>;
```

```ts
FieldLikeAPI.getInfo
```

--------------------------------

### useTypedAppFormContext()

Source: https://tanstack.com/form/latest/docs/framework/react/reference/functions/createFormHook.md

Gets a typed form from the `<form.AppForm />` context. It's recommended to use `withForm` whenever possible.

```APIDOC
## useTypedAppFormContext()

### Description
Gets a typed form from the `<form.AppForm />` context. It's recommended to use `withForm` whenever possible.

### Type Parameters
- **TFormData** (`TFormData`)
- **TOnMount** (`TOnMount` *extends* ... | ...)
- **TOnChange** (`TOnChange` *extends* ... | ...)
- **TOnChangeAsync** (`TOnChangeAsync` *extends* ... | ...)
- **TOnBlur** (`TOnBlur` *extends* ... | ...)
- **TOnBlurAsync** (`TOnBlurAsync` *extends* ... | ...)
- **TOnSubmit** (`TOnSubmit` *extends* ... | ...)
- **TOnSubmitAsync** (`TOnSubmitAsync` *extends* ... | ...)
- **TOnDynamic** (`TOnDynamic` *extends* ... | ...)
- **TOnDynamicAsync** (`TOnDynamicAsync` *extends* ... | ...)
- **TOnServer** (`TOnServer` *extends* ... | ...)
- **TSubmitMeta** (`TSubmitMeta`)

### Parameters
- **_props** (`FormOptions`<..., ..., ..., ..., ..., ..., ..., ..., ..., ..., ..., ...>)

### Returns
`AppFieldExtendedReactFormApi` <..., ..., ..., ..., ..., ..., ..., ..., ..., ..., ..., ..., ..., ...>
```

--------------------------------

### TanStack Form with Lit Example

Source: https://tanstack.com/form/latest/docs/overview.md

This snippet shows a complete Lit component using TanStack Form. It includes form initialization, field definitions with validation, and rendering of form elements and error messages. Use this for a full-fledged form implementation in Lit.

```typescript
import { LitElement, html, nothing } from 'lit'
import { customElement } from 'lit/decorators.js'

import { TanStackFormController } from '@tanstack/lit-form'
import { repeat } from 'lit/directives/repeat.js'

@customElement('tanstack-form-demo')
export class TanStackFormDemo extends LitElement {
  #form = new TanStackFormController(this, {
    defaultValues: {
      firstName: '',
      lastName: '',
    },
    onSubmit({ value }) {
      // Do something with form data
      console.log(value)
    },
  })

  render() {
    return html`
      <form
        @submit=${(e: Event) => {
          e.preventDefault()
          e.stopPropagation()
          this.#form.api.handleSubmit()
        }}
      >
          ${this.#form.field(
            {
              name: `firstName`,
              validators: {
                onChange: ({ value }) =>
                  !value
                    ? 'A first name is required'
                    : value.length < 3
                      ? 'First name must be at least 3 characters'
                      : undefined,
                onChangeAsyncDebounceMs: 500,
                onChangeAsync: async ({ value }) => {
                  await new Promise((resolve) => setTimeout(resolve, 1000))
                  return (
                    value.includes('error') &&
                    'No "error" allowed in first name'
                  )
                },
              },
            },
            (field) => {
              return html` <div>
                <label for="${field.name}">First Name:</label>
                <input
                  id="${field.name}"
                  name="${field.name}"
                  .value="${field.state.value}"
                  @blur="${() => field.handleBlur()}"
                  @input="${(e: Event) => {
                    const target = e.target as HTMLInputElement
                    field.handleChange(target.value)
                  }}"
                />
                ${field.state.meta.isTouched && !field.state.meta.isValid
                  ? html`${repeat(
                      field.state.meta.errors,
                      (__, idx) => idx,
                      (error) => {
                        return html`<div style="color: red;">${error}</div>`
                      },
                    )}`
                  : nothing}
                ${field.state.meta.isValidating
                  ? html`<p>Validating...</p>`
                  : nothing}
              </div>`
            },
          )}
        </div>
        <div>
          ${this.#form.field(
            {
              name: `lastName`,
            },
            (field) => {
              return html` <div>
                <label for="${field.name}">Last Name:</label>
                <input
                  id="${field.name}"
                  name="${field.name}"
                  .value="${field.state.value}"
                  @blur="${() => field.handleBlur()}"
                  @input="${(e: Event) => {
                    const target = e.target as HTMLInputElement
                    field.handleChange(target.value)
                  }}"
                />
              </div>`
            },
          )}
        </div>

        <button type="submit" ?disabled=${this.#form.api.state.isSubmitting}>
          ${this.#form.api.state.isSubmitting ? '...' : 'Submit'}
        </button>
        <button
          type="button"
          @click=${() => {
            this.#form.api.reset()
          }}
        >
          Reset
        </button>
      </form>
    `
  }
}

```

--------------------------------

### Implementing Dynamic Array Fields in TanStack Form

Source: https://tanstack.com/form/latest/docs/framework/react/guides/arrays.md

Demonstrates the basic setup for an array field using the mode='array' prop. It shows how to map over the array state to render fields and use pushValue to dynamically add new entries.

```jsx
function App() {
  const form = useForm({
    defaultValues: {
      people: [],
    },
  })

  return (
    <form.Field name="people" mode="array">
      {(field) => (
        <div>
          {field.state.value.map((_, i) => {
            // ...
          })}
          <button onClick={() => field.pushValue({ name: '', age: 0 })} type="button">
            Add person
          </button>
        </div>
      )}
    </form.Field>
  )
}
```

--------------------------------

### Field-Level Listeners

Source: https://tanstack.com/form/latest/docs/framework/react/guides/listeners.md

Demonstrates how to use the `listeners` API on a form field to react to events like `onChange`. This example shows how changing the 'country' field resets the 'province' field.

```APIDOC
## Field-Level Listeners

### Description
Attaches listeners to individual form fields to react to specific events.

### Method
N/A (Configuration within `useForm`)

### Endpoint
N/A

### Parameters
#### Field Configuration
- **listeners** (object) - Optional - An object containing event listener functions.
  - **onChange** (function) - Callback function executed when the field's value changes.
  - **onBlur** (function) - Callback function executed when the field loses focus.
  - **onMount** (function) - Callback function executed when the field is mounted.
  - **onUnmount** (function) - Callback function executed when the field is unmounted.

### Request Example
```tsx
<form.Field
  name="country"
  listeners={{
    onChange: ({ value }) => {
      console.log(`Country changed to: ${value}, resetting province`)
      form.setFieldValue('province', '')
    },
  }}
>
  {(field) => (
    <label>
      <div>Country</div>
      <input
        value={field.state.value}
        onChange={(e) => field.handleChange(e.target.value)}
      />
    </label>
  )}
</form.Field>
```

### Response
N/A (Side effects are triggered)

### Error Handling
N/A
```

--------------------------------

### Integrate TanStack Form with Mantine Components

Source: https://tanstack.com/form/latest/docs/framework/react/guides/ui-libraries.md

This example demonstrates how to use the useForm hook and Field component to bind Mantine's TextInput and Checkbox components to TanStack Form state.

```tsx
import { TextInput, Checkbox } from '@mantine/core'
import { useForm } from '@tanstack/react-form'

export default function App() {
  const { Field, handleSubmit, state } = useForm({
    defaultValues: {
      name: '',
      isChecked: false,
    },
    onSubmit: async ({ value }) => {
      console.log(value)
    },
  })

  return (
    <>
      <form
        onSubmit={(e) => {
          e.preventDefault()
          handleSubmit()
        }}
      >
        <Field
          name="name"
          children={({ state, handleChange, handleBlur }) => (
            <TextInput
              defaultValue={state.value}
              onChange={(e) => handleChange(e.target.value)}
              onBlur={handleBlur}
              placeholder="Enter your name"
            />
          )}
        />
        <Field
          name="isChecked"
          children={({ state, handleChange, handleBlur }) => (
            <Checkbox
              onChange={(e) => handleChange(e.target.checked)}
              onBlur={handleBlur}
              checked={state.value}
            />
          )}
        />
      </form>
      <div>
        <pre>{JSON.stringify(state.values, null, 2)}</pre>
      </div>
    </>
  )
}
```

--------------------------------

### Implement Asynchronous Validation

Source: https://tanstack.com/form/latest/docs/framework/react/guides/validation.md

Use onChangeAsync or onBlurAsync to perform network-based validation. The example demonstrates a delayed validation check for an age field.

```tsx
<form.Field
  name="age"
  validators={{
    onChangeAsync: async ({ value }) => {
      await new Promise((resolve) => setTimeout(resolve, 1000))
      return value < 13 ? 'You must be 13 to make an account' : undefined
    },
  }}
>
  {(field) => (
    <>
      <label htmlFor={field.name}>Age:</label>
      <input
        id={field.name}
        name={field.name}
        value={field.state.value}
        type="number"
        onChange={(e) => field.handleChange(e.target.valueAsNumber)}
      />
      {!field.state.meta.isValid && (
        <em role="alert">{field.state.meta.errors.join(', ')}</em>
      )}
    </>
  )}
</form.Field>
```

--------------------------------

### Implement field-level listeners

Source: https://tanstack.com/form/latest/docs/framework/react/guides/listeners.md

Demonstrates how to use the listeners property within a form field to react to changes, such as resetting dependent fields. This example shows an onChange listener that updates another field's value.

```tsx
function App() {
  const form = useForm({
    defaultValues: {
      country: '',
      province: '',
    },
  })

  return (
    <div>
      <form.Field
        name="country"
        listeners={{
          onChange: ({ value }) => {
            console.log(`Country changed to: ${value}, resetting province`)
            form.setFieldValue('province', '')
          },
        }}
      >
        {(field) => (
          <label>
            <div>Country</div>
            <input
              value={field.state.value}
              onChange={(e) => field.handleChange(e.target.value)}
            />
          </label>
        )}
      </form.Field>

      <form.Field name="province">
        {(field) => (
          <label>
            <div>Province</div>
            <input
              value={field.state.value}
              onChange={(e) => field.handleChange(e.target.value)}
            />
          </label>
        )}
      </form.Field>
    </div>
  )
}
```

--------------------------------

### useSelector<TSource, TSelected>(source, selector?, options?)

Source: https://tanstack.com/form/latest/docs/framework/react/reference/functions/useSelector.md

Selects a slice of state from an atom or store and subscribes the component to that selection. It works with any source that exposes get() and subscribe() methods.

```APIDOC
## useSelector<TSource, TSelected>(source, selector?, options?)

### Description
Selects a slice of state from an atom or store and subscribes the component to that selection. This is the primary React read hook for TanStack Store.

### Parameters
- **source** (SelectionSource<TSource>) - Required - The atom or store to subscribe to.
- **selector?** ((snapshot) => TSelected) - Optional - A function to select a specific slice of the state.
- **options?** (UseSelectorOptions<TSelected>) - Optional - Configuration options for the selector.

### Returns
- **TSelected** - The selected slice of state.

### Examples
```tsx
const count = useSelector(counterStore, (state) => state.count)
const value = useSelector(countAtom)
```
```

--------------------------------

### useStore<TSource, TSelected>(source, selector?, compare?)

Source: https://tanstack.com/form/latest/docs/framework/react/reference/variables/useStore.md

A deprecated hook that subscribes to a store and returns a selected value. It accepts a source object with get and subscribe methods, an optional selector function, and an optional comparison function.

```APIDOC
## useStore

### Description
Deprecated hook used to select and subscribe to state from a store. Use `useSelector` instead.

### Signature
`const useStore: <TSource, TSelected>(source, selector?, compare?) => TSelected;`

### Parameters
- **source** (object) - Required - An object containing `get()` and `subscribe(listener)` methods.
- **selector** (function) - Optional - A function that takes the snapshot and returns the selected value.
- **compare** (function) - Optional - A function to compare the previous and next selected values to determine if a re-render is needed.

### Returns
- **TSelected** - The selected value from the store.

### Example
```tsx
const count = useStore(counterStore, (state) => state.count)
```
```

--------------------------------

### Validate Array Fields Starting From

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldGroupApi.md

Validates children of a specified array field starting from a given index. Use this for partial array validation.

```typescript
validateArrayFieldsStartingFrom<TField>(
   field,
   index,
cause): Promise<unknown[]>;

```

--------------------------------

### Get all errors

Source: https://tanstack.com/form/latest/docs/reference/classes/FormApi.md

Retrieves both form-level and field-level errors.

```ts
getAllErrors(): object;
```

```ts
fields: Record<DeepKeys<TFormData>, {
  errorMap: ValidationErrorMap;
  errors: ValidationError[];
}>;
```

```ts
form: object;
```

```ts
errorMap: ValidationErrorMap<UnwrapFormValidateOrFn<TOnMount>, UnwrapFormValidateOrFn<TOnChange>, UnwrapFormAsyncValidateOrFn<TOnChangeAsync>, UnwrapFormValidateOrFn<TOnBlur>, UnwrapFormAsyncValidateOrFn<TOnBlurAsync>, UnwrapFormValidateOrFn<TOnSubmit>, UnwrapFormAsyncValidateOrFn<TOnSubmitAsync>, UnwrapFormValidateOrFn<TOnDynamic>, UnwrapFormAsyncValidateOrFn<TOnDynamicAsync>, UnwrapFormAsyncValidateOrFn<TOnServer>>;
```

```ts
errors: NonNullable<
  | UnwrapFormValidateOrFn<TOnMount>
  | UnwrapFormValidateOrFn<TOnChange>
  | UnwrapFormAsyncValidateOrFn<TOnChangeAsync>
  | UnwrapFormValidateOrFn<TOnBlur>
  | UnwrapFormAsyncValidateOrFn<TOnBlurAsync>
  | UnwrapFormValidateOrFn<TOnSubmit>
  | UnwrapFormAsyncValidateOrFn<TOnSubmitAsync>
  | UnwrapFormValidateOrFn<TOnDynamic>
  | UnwrapFormAsyncValidateOrFn<TOnDynamicAsync>
  | UnwrapFormAsyncValidateOrFn<TOnServer>>[];
```

--------------------------------

### Create a form instance with useForm

Source: https://tanstack.com/form/latest/docs/framework/react/guides/basic-concepts.md

Initialize a form instance using pre-defined options and an onSubmit handler.

```tsx
const form = useForm({
  ...formOpts,
  onSubmit: async ({ value }) => {
    // Do something with form data
    console.log(value)
  },
})
```

--------------------------------

### Get formId

Source: https://tanstack.com/form/latest/docs/reference/classes/FormApi.md

Retrieves the unique identifier for the form instance.

```ts
get formId(): string;
```

--------------------------------

### useAppForm()

Source: https://tanstack.com/form/latest/docs/framework/react/reference/functions/createFormHook.md

Initializes a new form instance with specified validation and submission logic.

```APIDOC
## useAppForm()

### Description
Initializes a form instance using the provided configuration options, including validation and submission handlers.

### Parameters
- **props** (FormOptions) - Required - Configuration object containing validation and submission logic for the form.

### Returns
- **AppFieldExtendedReactFormApi** - The form API instance for managing form state and interactions.
```

--------------------------------

### useAppForm()

Source: https://tanstack.com/form/latest/docs/framework/react/reference/functions/createFormHook.md

Initializes the form with specific data and event handlers.

```APIDOC
## useAppForm()

### Description
Initializes the form hook with form options and returns the API for managing form state.

### Parameters
#### props
- **props** (FormOptions) - Required - Configuration options for the form including data, mount, change, blur, and submit handlers.

### Response
- **AppFieldExtendedReactFormApi** - The API object for interacting with the form.
```

--------------------------------

### Get Field Meta

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldApi.md

Retrieves the metadata associated with the field.

```ts
getMeta(): FieldLikeMeta<TParentData, TName, TData, TOnMount, TOnChange, TOnChangeAsync, TOnBlur, TOnBlurAsync, TOnSubmit, TOnSubmitAsync, TOnDynamic, TOnDynamicAsync, TFormOnMount, TFormOnChange, TFormOnChangeAsync, TFormOnBlur, TFormOnBlurAsync, TFormOnSubmit, TFormOnSubmitAsync, TFormOnDynamic, TFormOnDynamicAsync>;
```

```ts
FieldLikeAPI.getMeta
```

--------------------------------

### Get Field State

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldApi.md

Access the current state of the field.

```ts
get state(): FieldLikeState<TParentData, TName, TData, TOnMount, TOnChange, TOnChangeAsync, TOnBlur, TOnBlurAsync, TOnSubmit, TOnSubmitAsync, TOnDynamic, TOnDynamicAsync, TFormOnMount, TFormOnChange, TFormOnChangeAsync, TFormOnBlur, TFormOnBlurAsync, TFormOnSubmit, TFormOnSubmitAsync, TFormOnDynamic, TFormOnDynamicAsync>;
```

--------------------------------

### Get State Accessor

Source: https://tanstack.com/form/latest/docs/reference/classes/FormGroupApi.md

Retrieves the current field state. Returns FormGroupStoreState.

```typescript
get state(): FormGroupStoreState<TParentData, TName, TData, TOnMount, TOnChange, TOnChangeAsync, TOnBlur, TOnBlurAsync, TOnSubmit, TOnSubmitAsync, TOnDynamic, TOnDynamicAsync, TFormOnMount, TFormOnChange, TFormOnChangeAsync, TFormOnBlur, TFormOnBlurAsync, TFormOnSubmit, TFormOnSubmitAsync, TFormOnDynamic, TFormOnDynamicAsync>;
```

--------------------------------

### Initialize React Application with Devtools

Source: https://tanstack.com/form/latest/docs/framework/react/examples/large-form

Configures the root entry point for a React application, including the TanStack Devtools and form devtools plugin.

```typescript
import * as React from 'react'
import { createRoot } from 'react-dom/client'

import { TanStackDevtools } from '@tanstack/react-devtools'
import { formDevtoolsPlugin } from '@tanstack/react-form-devtools'

import App from './App.tsx'

const rootElement = document.getElementById('root')!

createRoot(rootElement).render(
  <React.StrictMode>
    <App />

    <TanStackDevtools
      config={{ hideUntilHover: true }}
      plugins={[formDevtoolsPlugin()]}
    />
  </React.StrictMode>,
)
```

--------------------------------

### Form-Level Listeners

Source: https://tanstack.com/form/latest/docs/framework/react/guides/listeners.md

Illustrates how to configure listeners at the form level to handle events like `onMount` and `onSubmit`, and how `onChange` and `onBlur` events propagate.

```APIDOC
## Form-Level Listeners

### Description
Configures listeners at the form level to capture global form events like mount, submit, and changes across all fields.

### Method
N/A (Configuration within `useForm`)

### Endpoint
N/A

### Parameters
#### Form Configuration
- **listeners** (object) - Optional - An object containing form-level event listener functions.
  - **onMount** (function) - Callback function executed when the form is mounted. Receives `formApi`.
  - **onSubmit** (function) - Callback function executed when the form is submitted. Receives `formApi`.
  - **onChange** (function) - Callback function executed when any field's value changes. Receives `formApi` and `fieldApi`.
  - **onBlur** (function) - Callback function executed when any field loses focus. Receives `formApi` and `fieldApi`.
  - **onChangeDebounceMs** (number) - Optional - Debounce time in milliseconds for the form-level `onChange` event.
  - **onBlurDebounceMs** (number) - Optional - Debounce time in milliseconds for the form-level `onBlur` event.

### Request Example
```tsx
const form = useForm({
  listeners: {
    onMount: ({ formApi }) => {
      // custom logging service
      loggingService('mount', formApi.state.values)
    },

    onChange: ({ formApi, fieldApi }) => {
      // autosave logic
      if (formApi.state.isValid) {
        formApi.handleSubmit()
      }

      // fieldApi represents the field that triggered the event.
      console.log(fieldApi.name, fieldApi.state.value)
    },
    onChangeDebounceMs: 500,
  },
})
```

### Response
N/A (Side effects are triggered)

### Error Handling
N/A
```

--------------------------------

### validateArrayFieldsStartingFrom()

Source: https://tanstack.com/form/latest/docs/reference/classes/FormGroupApi.md

Validates array fields starting from a specified index within the form group.

```APIDOC
## validateArrayFieldsStartingFrom()

### Description
Validates array fields starting from a specified index.

### Method
`validateArrayFieldsStartingFrom<TField>(field, index, cause)`

### Type Parameters
- **TField**: Must extend `string`.

### Parameters
#### Parameters
- **field** (`TField`) - The name of the field to start validation from.
- **index** (`number`) - The starting index for validation.
- **cause** (`ValidationCause`) - The cause of the validation.

### Returns
`Promise<unknown[]>` - A promise that resolves to an array of validation errors.
```

--------------------------------

### Create a standalone form instance

Source: https://tanstack.com/form/latest/docs/framework/react/guides/basic-concepts.md

Initialize a form instance directly without using external form options.

```tsx
interface User {
  firstName: string
  lastName: string
  hobbies: Array<string>
}
const defaultUser: User = { firstName: '', lastName: '', hobbies: [] }

const form = useForm({
  defaultValues: defaultUser,
  onSubmit: async ({ value }) => {
    // Do something with form data
    console.log(value)
  },
})
```

--------------------------------

### Constructor

Source: https://tanstack.com/form/latest/docs/reference/classes/FormGroupApi.md

Initializes a new instance of the FormGroupApi class. It accepts an options object to configure the form group's behavior and data.

```APIDOC
## Constructor

### FormGroupApi

```ts
new FormGroupApi<TParentData, TName, TData, TOnMount, TOnChange, TOnChangeAsync, TOnBlur, TOnBlurAsync, TOnSubmit, TOnSubmitAsync, TOnDynamic, TOnDynamicAsync, TSubmitMeta, TFormOnMount, TFormOnChange, TFormOnChangeAsync, TFormOnBlur, TFormOnBlurAsync, TFormOnSubmit, TFormOnSubmitAsync, TFormOnDynamic, TFormOnDynamicAsync, TFormOnServer, TParentSubmitMeta>(opts: FormGroupApiOptions<...>);
```

#### Parameters

- **opts** (FormGroupApiOptions<...>) - An options object used to configure the FormGroupApi instance.
```

--------------------------------

### Get state

Source: https://tanstack.com/form/latest/docs/reference/classes/FormApi.md

Retrieves the current state of the form, including all validation and data properties.

```ts
get state(): FormState<TFormData, TOnMount, TOnChange, TOnChangeAsync, TOnBlur, TOnBlurAsync, TOnSubmit, TOnSubmitAsync, TOnDynamic, TOnDynamicAsync, TOnServer>;
```

--------------------------------

### Create and Render a Form with Solid

Source: https://tanstack.com/form/latest/docs/overview.md

Use `createForm` to initialize a form with default values and an onSubmit handler. Render form fields and a submit button using Solid's JSX syntax. The `form.Field` component handles individual fields, and `form.Subscribe` allows subscribing to form state changes.

```typescript
/* @refresh reload */
import { render } from 'solid-js/web'
import { createForm } from '@tanstack/solid-form'
import { FieldInfo } from './FieldInfo.tsx';

function App() {
  const form = createForm(() => ({
    defaultValues: {
      firstName: '',
      lastName: '',
    },
    onSubmit: async ({ value }) => {
      // Do something with form data
      console.log(value)
    },
  }))

  return (
    <div>
      <h1>Simple Form Example</h1>
      <form
        onSubmit={(e) => {
          e.preventDefault()
          e.stopPropagation()
          form.handleSubmit()
        }}
      >
        <div>
          {/* A type-safe field component*/}
          <form.Field
            name="firstName"
            validators={{
              onChange: ({ value }) =>
                !value
                  ? 'A first name is required'
                  : value.length < 3
                    ? 'First name must be at least 3 characters'
                    : undefined,
              onChangeAsyncDebounceMs: 500,
              onChangeAsync: async ({ value }) => {
                await new Promise((resolve) => setTimeout(resolve, 1000))
                return (
                  value.includes('error') && 'No "error" allowed in first name'
                )
              },
            }}
            children={(field) => {
              // Avoid hasty abstractions. Render props are great!
              return (
                <>
                  <label for={field().name}>First Name:</label>
                  <input
                    id={field().name}
                    name={field().name}
                    value={field().state.value}
                    onBlur={field().handleBlur}
                    onInput={(e) => field().handleChange(e.target.value)}
                  />
                  <FieldInfo field={field()} />
                </>
              )
            }}
          />
        </div>
        <div>
          <form.Field
            name="lastName"
            children={(field) => (
              <>
                <label for={field().name}>Last Name:</label>
                <input
                  id={field().name}
                  name={field().name}
                  value={field().state.value}
                  onBlur={field().handleBlur}
                  onInput={(e) => field().handleChange(e.target.value)}
                />
                <FieldInfo field={field()} />
              </>
            )}
          />
        </div>
        <form.Subscribe
          selector={(state) => ({
            canSubmit: state.canSubmit,
            isSubmitting: state.isSubmitting,
          })}
          children={(state) => {
            return (
              <button type="submit" disabled={!state().canSubmit}>
                {state().isSubmitting ? '...' : 'Submit'}
              </button>
            )
          }}
        />
      </form>
    </div>
  )
}

const root = document.getElementById('root')

render(() => <App />, root!)

```

--------------------------------

### Get Field Value (Deprecated)

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldApi.md

Retrieves the current field value. Use field.state.value instead.

```ts
getValue(): TData;
```

--------------------------------

### getFieldValue

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldGroupApi.md

Gets the value of the specified field. This method retrieves the current value associated with a given field name.

```APIDOC
## getFieldValue()

### Description
Gets the value of the specified field.

### Method
Not applicable (TypeScript method)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Parameters
- **field** (TField) - Description: The name of the field for which to retrieve the value.

### Returns
- **DeepValue<TFieldGroupData, TField>** - The value of the specified field.
```

--------------------------------

### mount()

Source: https://tanstack.com/form/latest/docs/reference/classes/FormApi.md

Mounts the form instance and returns a cleanup function.

```ts
mount(): () => void;
```

--------------------------------

### Returning Number Errors from Validators

Source: https://tanstack.com/form/latest/docs/framework/react/guides/custom-errors.md

Illustrates using numbers as error values, for example, to indicate a required quantity.

```APIDOC
## Returning Number Errors

### Description
Validates the age field, returning the difference needed to reach the minimum age if the current age is below 18.

### Method
N/A (Component Configuration)

### Endpoint
N/A

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```tsx
<form.Field
  name="age"
  validators={{
    onChange: ({ value }) => (value < 18 ? 18 - value : undefined),
  }}
/>
```

### Response
#### Success Response (200)
N/A

#### Response Example
N/A

## Displaying Number Errors

### Description
Shows how to display a numeric error value, such as the number of years remaining to meet an age requirement.

### Method
N/A (UI Rendering)

### Endpoint
N/A

### Parameters
None

### Request Example
```tsx
// TypeScript knows the error is a number based on your validator
<div className="error">
  You need {field.state.meta.errors[0]} more years to be eligible
</div>
```

### Response
#### Success Response (200)
N/A

#### Response Example
N/A
```

--------------------------------

### Basic FormGroup Usage

Source: https://tanstack.com/form/latest/docs/framework/react/guides/form-groups.md

Demonstrates how to create a form and reference its FormGroup component. The `group` prop provides access to form-like methods within the sub-form.

```tsx
const form = useForm({
    defaultValues: {
        step1: {
            name: ""
        },
        step2: {
            age: 0
        }
    }
})

return (
    <form.FormGroup
        name="step1"
        children={group => (
            // `group` here has all of the form-like methods you'd expect like `deleteField` or `insertFieldValue`
            // ...
        )}
    />
)
```

--------------------------------

### Initialize TanStack Form with Async Data using React and TanStack Query

Source: https://tanstack.com/form/latest/docs/framework/react/guides/async-initial-values.md

This snippet shows how to fetch data asynchronously using TanStack Query and then use that data to initialize a TanStack Form. It includes handling the loading state before the data is available. Dependencies include '@tanstack/react-form' and '@tanstack/react-query'. The input is an asynchronous data fetch, and the output is a form component with initial values set.

```tsx
import { useForm } from '@tanstack/react-form'
import { useQuery } from '@tanstack/react-query'

export default function App() {
  const {data, isLoading} = useQuery({
    queryKey: ['data'],
    queryFn: async () => {
      await new Promise((resolve) => setTimeout(resolve, 1000))
      return {firstName: 'FirstName', lastName: "LastName"}
    }
  })

  const form = useForm({
    defaultValues: {
      firstName: data?.firstName ?? '',
      lastName: data?.lastName ?? '',
    },
    onSubmit: async ({ value }) => {
      // Do something with form data
      console.log(value)
    },
  })

  if (isLoading) return <p>Loading...</p>

  return (
    // ...
  )
}
```

--------------------------------

### getFieldMeta

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldGroupApi.md

Gets the metadata of the specified field. This method allows you to retrieve information about a specific field within the form group.

```APIDOC
## getFieldMeta()

### Description
Gets the metadata of the specified field.

### Method
Not applicable (TypeScript method)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Parameters
- **field** (TField) - Description: The name of the field for which to retrieve metadata.

### Returns
- **AnyFieldLikeMeta** | **undefined** - The metadata of the field, or undefined if the field does not exist.
```

--------------------------------

### Get Field Value

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldGroupApi.md

Retrieves the current value of a specific form field. This is useful for accessing form data programmatically.

```typescript
getFieldValue<TField>(field): DeepValue<TFieldGroupData, TField>;
```

--------------------------------

### mount()

Source: https://tanstack.com/form/latest/docs/reference/classes/FieldApi.md

Mounts the field instance to the form.

```APIDOC
## mount()

### Description
Mounts the field instance to the form.

### Returns
- **Function** - A cleanup function to unmount the field instance.
```

--------------------------------

### Generate a UUID String

Source: https://tanstack.com/form/latest/docs/reference/functions/uuid.md

Call the `uuid()` function to get a unique string identifier. This function requires no arguments and returns a string.

```typescript
function uuid(): string;
```

--------------------------------

### Implement client-side form component

Source: https://tanstack.com/form/latest/docs/framework/react/guides/ssr.md

Use the loader to sync server state and implement the form component with client-side validation.

```tsx
// app/routes/index.tsx
import { createFileRoute } from '@tanstack/react-router'
import {
  mergeForm,
  useForm,
  useSelector,
  useTransform,
} from '@tanstack/react-form-start'

export const Route = createFileRoute('/')({
  component: Home,
  loader: async () => ({
    state: await getFormDataFromServer(),
  }),
})

function Home() {
  const { state } = Route.useLoaderData()
  const form = useForm({
    ...formOpts,
    transform: useTransform((baseForm) => mergeForm(baseForm, state), [state]),
  })

  const formErrors = useSelector(form.store, (formState) => formState.errors)

  return (
    <form action={handleForm.url} method="post" encType={'multipart/form-data'}>
      {formErrors.map((error) => (
        <p key={error as string}>{error}</p>
      ))}

      <form.Field
        name="age"
        validators={{
          onChange: ({ value }) =>
            value < 8 ? 'Client validation: You must be at least 8' : undefined,
        }}
      >
        {(field) => {
          return (
            <div>
              <input
                name={field.name}
                type="number"
                value={field.state.value}
                onChange={(e) => field.handleChange(e.target.valueAsNumber)}
              />
              {field.state.meta.errors.map((error) => (
                <p key={error as string}>{error}</p>
              ))}
            </div>
          )
        }}
      </form.Field>
      <form.Subscribe
        selector={(formState) => [formState.canSubmit, formState.isSubmitting]}
      >
        {([canSubmit, isSubmitting]) => (
          <button type="submit" disabled={!canSubmit}>
            {isSubmitting ? '...' : 'Submit'}
          </button>
        )}
      </form.Subscribe>
    </form>
  )
}
```

--------------------------------

### Get Form Info

Source: https://tanstack.com/form/latest/docs/reference/classes/FormGroupApi.md

Retrieves the overall information object for the form group. This includes details about the form's state and structure.

```typescript
getInfo(): FieldInfo<TParentData>;
```

--------------------------------

### Initialize Custom Form Hook

Source: https://tanstack.com/form/latest/docs/framework/react/guides/form-composition.md

Configure a custom form hook using the previously created contexts.

```tsx
import { createFormHook } from '@tanstack/react-form'
import { createFormHookContexts } from './AppFormContext'

const { useAppForm } = createFormHook({
  fieldContext,
  formContext,
  // We'll learn more about these options later
  fieldComponents: {},
  formComponents: {},
})

function App() {
  const form = useAppForm({
    // Supports all useForm options
    defaultValues: {
      firstName: 'John',
      lastName: 'Doe',
    },
  })

  return <form.Field /> // ...
```

--------------------------------

### Get Field Value

Source: https://tanstack.com/form/latest/docs/reference/classes/FormGroupApi.md

Retrieves the value of a specific field within the form group. The type of the returned value is deeply nested.

```typescript
getFieldValue<TField>(field): DeepValue<TParentData, TField>;
```

--------------------------------

### Configure form options with formOptions

Source: https://tanstack.com/form/latest/docs/framework/react/guides/basic-concepts.md

Define reusable form configuration options including default values.

```tsx
interface User {
  firstName: string
  lastName: string
  hobbies: Array<string>
}
const defaultUser: User = { firstName: '', lastName: '', hobbies: [] }

const formOpts = formOptions({
  defaultValues: defaultUser,
})
```
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