Fix onSubmit usage

docs/framework/react/quick-start.md

@@ -13,12 +13,9 @@ import { useForm } from '@tanstack/react-form'
 export default function App() {
   const form = useForm({
     // Memoize your default values to prevent re-renders
-    defaultValues: React.useMemo(
-      () => ({
-        fullName: '',
-      }),
-      [],
-    ),
+    defaultValues: {
+      fullName: '',
+    },
     onSubmit: async (values) => {
       // Do something with form data
       console.log(values)

docs/overview.md

@@ -44,14 +44,10 @@ function FieldInfo({ field }: { field: FieldApi<any, any> }) {
 
 export default function App() {
   const form = useForm({
-    // Memoize your default values to prevent re-renders
-    defaultValues: React.useMemo(
-      () => ({
-        firstName: '',
-        lastName: '',
-      }),
-      [],
-    ),
+    defaultValues: {
+      firstName: '',
+      lastName: '',
+    },
     onSubmit: async (values) => {
       // Do something with form data
       console.log(values)

examples/react/simple/src/index.tsx

@@ -17,13 +17,10 @@ function FieldInfo({ field }: { field: FieldApi<any, any> }) {
 export default function App() {
   const form = useForm({
     // Memoize your default values to prevent re-renders
-    defaultValues: React.useMemo(
-      () => ({
-        firstName: "",
-        lastName: "",
-      }),
-      [],
-    ),
+    defaultValues: {
+      firstName: "",
+      lastName: "",
+    },
     onSubmit: async (values) => {
       // Do something with form data
       console.log(values);

packages/form-core/src/FormApi.ts

@@ -69,21 +69,20 @@ function getDefaultFormState<TData>(
   defaultState: Partial<FormState<TData>>,
 ): FormState<TData> {
   return {
-    values: {} as any,
-    fieldMeta: {} as any,
-    canSubmit: true,
-    isFieldsValid: false,
-    isFieldsValidating: false,
-    isFormValid: false,
-    isFormValidating: false,
-    isSubmitted: false,
-    isSubmitting: false,
-    isTouched: false,
-    isValid: false,
-    isValidating: false,
-    submissionAttempts: 0,
-    formValidationCount: 0,
-    ...defaultState,
+    values: defaultState.values ?? ({} as never),
+    fieldMeta: defaultState.fieldMeta ?? ({} as never),
+    canSubmit: defaultState.canSubmit ?? true,
+    isFieldsValid: defaultState.isFieldsValid ?? false,
+    isFieldsValidating: defaultState.isFieldsValidating ?? false,
+    isFormValid: defaultState.isFormValid ?? false,
+    isFormValidating: defaultState.isFormValidating ?? false,
+    isSubmitted: defaultState.isSubmitted ?? false,
+    isSubmitting: defaultState.isSubmitting ?? false,
+    isTouched: defaultState.isTouched ?? false,
+    isValid: defaultState.isValid ?? false,
+    isValidating: defaultState.isValidating ?? false,
+    submissionAttempts: defaultState.submissionAttempts ?? 0,
+    formValidationCount: defaultState.formValidationCount ?? 0,
   }
 }
 
@@ -156,15 +155,18 @@ export class FormApi<TFormData> {
     this.store.batch(() => {
       const shouldUpdateValues =
         options.defaultValues &&
-        options.defaultValues !== this.options.defaultValues
+        options.defaultValues !== this.options.defaultValues &&
+        !this.state.isTouched
 
       const shouldUpdateState =
-        options.defaultState !== this.options.defaultState
+        options.defaultState !== this.options.defaultState &&
+        !this.state.isTouched
 
       this.store.setState(() =>
         getDefaultFormState(
           Object.assign(
             {},
+            this.state,
             // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
             shouldUpdateState ? options.defaultState : {},
             // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition

packages/form-core/src/tests/FormApi.spec.ts

@@ -213,4 +213,58 @@ describe('form api', () => {
 
     expect(form.getFieldValue('names')).toStrictEqual(['one', 'three', 'two'])
   })
+
+  it('should not wipe values when updating', () => {
+    const form = new FormApi({
+      defaultValues: {
+        name: 'test',
+      },
+    })
+
+    form.setFieldValue('name', 'other')
+
+    expect(form.getFieldValue('name')).toEqual('other')
+
+    form.update()
+
+    expect(form.getFieldValue('name')).toEqual('other')
+  })
+
+  it('should wipe default values when not touched', () => {
+    const form = new FormApi({
+      defaultValues: {
+        name: 'test',
+      },
+    })
+
+    expect(form.getFieldValue('name')).toEqual('test')
+
+    form.update({
+      defaultValues: {
+        name: 'other',
+      },
+    })
+
+    expect(form.getFieldValue('name')).toEqual('other')
+  })
+
+  it('should not wipe default values when touched', () => {
+    const form = new FormApi({
+      defaultValues: {
+        name: 'one',
+      },
+    })
+
+    expect(form.getFieldValue('name')).toEqual('one')
+
+    form.setFieldValue('name', 'two', { touch: true })
+
+    form.update({
+      defaultValues: {
+        name: 'three',
+      },
+    })
+
+    expect(form.getFieldValue('name')).toEqual('two')
+  })
 })

packages/react-form/src/tests/useForm.test.tsx

@@ -1,9 +1,9 @@
 /// <reference lib="dom" />
-import { render } from '@testing-library/react'
+import { render, waitFor } from '@testing-library/react'
 import userEvent from '@testing-library/user-event'
 import '@testing-library/jest-dom'
 import * as React from 'react'
-import { createFormFactory } from '..'
+import { createFormFactory, useForm } from '..'
 
 const user = userEvent.setup()
 
@@ -78,4 +78,50 @@ describe('useForm', () => {
     expect(await findByText('FirstName')).toBeInTheDocument()
     expect(queryByText('LastName')).not.toBeInTheDocument()
   })
+
+  it('should handle submitting properly', async () => {
+    function Comp() {
+      const [submittedData, setSubmittedData] = React.useState<{
+        firstName: string
+      } | null>(null)
+
+      const form = useForm({
+        defaultValues: {
+          firstName: 'FirstName',
+        },
+        onSubmit: (data) => {
+          setSubmittedData(data)
+        },
+      })
+
+      return (
+        <form.Provider>
+          <form.Field
+            name="firstName"
+            children={(field) => {
+              return (
+                <input
+                  value={field.state.value}
+                  onBlur={field.handleBlur}
+                  onChange={(e) => field.handleChange(e.target.value)}
+                  placeholder={'First name'}
+                />
+              )
+            }}
+          />
+          <button onClick={form.handleSubmit}>Submit</button>
+          {submittedData && <p>Submitted data: {submittedData.firstName}</p>}
+        </form.Provider>
+      )
+    }
+
+    const { findByPlaceholderText, getByText } = render(<Comp />)
+    const input = await findByPlaceholderText('First name')
+    await user.clear(input)
+    await user.type(input, 'OtherName')
+    await user.click(getByText('Submit'))
+    await waitFor(() =>
+      expect(getByText('Submitted data: OtherName')).toBeInTheDocument(),
+    )
+  })
 })

packages/react-form/src/types.ts

@@ -0,0 +1,8 @@
+import type { FieldOptions } from '@tanstack/form-core'
+
+export type UseFieldOptions<TData, TFormData> = FieldOptions<
+  TData,
+  TFormData
+> & {
+  mode?: 'value' | 'array'
+}

packages/react-form/src/useField.tsx

@@ -1,5 +1,4 @@
-import * as React from 'react'
-//
+import React, { useState } from 'react'
 import { useStore } from '@tanstack/react-store'
 import type {
   DeepKeys,
@@ -9,6 +8,8 @@ import type {
 } from '@tanstack/form-core'
 import { FieldApi, functionalUpdate } from '@tanstack/form-core'
 import { useFormContext, formContext } from './formContext'
+import { useIsomorphicLayoutEffect } from './utils/useIsomorphicLayoutEffect'
+import type { UseFieldOptions } from './types'
 
 declare module '@tanstack/form-core' {
   // eslint-disable-next-line no-shadow
@@ -17,13 +18,6 @@ declare module '@tanstack/form-core' {
   }
 }
 
-export type UseFieldOptions<TData, TFormData> = FieldOptions<
-  TData,
-  TFormData
-> & {
-  mode?: 'value' | 'array'
-}
-
 export type UseField<TFormData> = <TField extends DeepKeys<TFormData>>(
   opts?: { name: Narrow<TField> } & UseFieldOptions<
     DeepValue<TFormData, TField>,
@@ -37,7 +31,7 @@ export function useField<TData, TFormData>(
   // Get the form API either manually or from context
   const { formApi, parentFieldName } = useFormContext()
 
-  const [fieldApi] = React.useState<FieldApi<TData, TFormData>>(() => {
+  const [fieldApi] = useState<FieldApi<TData, TFormData>>(() => {
     const name = (
       typeof opts.index === 'number'
         ? [parentFieldName, opts.index, opts.name]
@@ -53,8 +47,13 @@ export function useField<TData, TFormData>(
     return api
   })
 
-  // Keep options up to date as they are rendered
-  fieldApi.update({ ...opts, form: formApi } as never)
+  /**
+   * fieldApi.update should not have any side effects. Think of it like a `useRef`
+   * that we need to keep updated every render with the most up-to-date information.
+   */
+  useIsomorphicLayoutEffect(() => {
+    fieldApi.update({ ...opts, form: formApi } as never)
+  })
 
   useStore(
     fieldApi.store as any,
@@ -66,7 +65,7 @@ export function useField<TData, TFormData>(
   )
 
   // Instantiates field meta and removes it when unrendered
-  React.useEffect(() => fieldApi.mount(), [fieldApi])
+  useIsomorphicLayoutEffect(() => fieldApi.mount(), [fieldApi])
 
   return fieldApi
 }

packages/react-form/src/useForm.tsx

@@ -2,9 +2,10 @@ import type { FormState, FormOptions } from '@tanstack/form-core'
 import { FormApi, functionalUpdate } from '@tanstack/form-core'
 import type { NoInfer } from '@tanstack/react-store'
 import { useStore } from '@tanstack/react-store'
-import React from 'react'
+import React, { type ReactNode, useState } from 'react'
 import { type UseField, type FieldComponent, Field, useField } from './useField'
 import { formContext } from './formContext'
+import { useIsomorphicLayoutEffect } from './utils/useIsomorphicLayoutEffect'
 
 declare module '@tanstack/form-core' {
   // eslint-disable-next-line no-shadow
@@ -17,15 +18,13 @@ declare module '@tanstack/form-core' {
     ) => TSelected
     Subscribe: <TSelected = NoInfer<FormState<TFormData>>>(props: {
       selector?: (state: NoInfer<FormState<TFormData>>) => TSelected
-      children:
-        | ((state: NoInfer<TSelected>) => React.ReactNode)
-        | React.ReactNode
+      children: ((state: NoInfer<TSelected>) => ReactNode) | ReactNode
     }) => any
   }
 }
 
 export function useForm<TData>(opts?: FormOptions<TData>): FormApi<TData> {
-  const [formApi] = React.useState(() => {
+  const [formApi] = useState(() => {
     // @ts-ignore
     const api = new FormApi<TData>(opts)
 
@@ -58,9 +57,13 @@ export function useForm<TData>(opts?: FormOptions<TData>): FormApi<TData> {
 
   formApi.useStore((state) => state.isSubmitting)
 
-  React.useEffect(() => {
+  /**
+   * formApi.update should not have any side effects. Think of it like a `useRef`
+   * that we need to keep updated every render with the most up-to-date information.
+   */
+  useIsomorphicLayoutEffect(() => {
     formApi.update(opts)
-  }, [formApi, opts])
+  })
 
   return formApi as any
 }

packages/react-form/src/utils/isBrowser.ts

@@ -0,0 +1,3 @@
+/* c8 ignore start */
+export const isBrowser = typeof window !== 'undefined'
+/* c8 ignore end */

packages/react-form/src/utils/useIsomorphicLayoutEffect.ts

@@ -0,0 +1,6 @@
+/* c8 ignore start */
+import { useEffect, useLayoutEffect } from 'react'
+import { isBrowser } from './isBrowser'
+
+export const useIsomorphicLayoutEffect = isBrowser ? useLayoutEffect : useEffect
+/* c8 ignore end */