fix: React adapter behavior has now been fixed

.changeset/wicked-ravens-shout.md

@@ -0,0 +1,6 @@
+---
+'@tanstack/react-form': patch
+'@tanstack/form-core': patch
+---
+
+Fix issues with methods not being present in React adapter

packages/form-core/src/FieldApi.ts

@@ -962,6 +962,11 @@ export type AnyFieldApi = FieldApi<
   any
 >
 
+/**
+ * We cannot use methods and must use arrow functions. Otherwise, our React adapters
+ * will break due to loss of the method when using spread.
+ */
+
 /**
  * A class representing the API for managing a form field.
  *
@@ -1908,7 +1913,7 @@ export class FieldApi<
   /**
    * Updates the field's errorMap
    */
-  setErrorMap(
+  setErrorMap = (
     errorMap: ValidationErrorMap<
       UnwrapFieldValidateOrFn<TName, TOnMount, TFormOnMount>,
       UnwrapFieldValidateOrFn<TName, TOnChange, TFormOnChange>,
@@ -1920,7 +1925,7 @@ export class FieldApi<
       UnwrapFieldValidateOrFn<TName, TOnDynamic, TFormOnDynamic>,
       UnwrapFieldAsyncValidateOrFn<TName, TOnDynamicAsync, TFormOnDynamicAsync>
     >,
-  ) {
+  ) => {
     this.setMeta((prev) => ({
       ...prev,
       errorMap: {
@@ -1997,7 +2002,7 @@ export class FieldApi<
   /**
    * @private
    */
-  triggerOnChangeListener() {
+  triggerOnChangeListener = () => {
     const formDebounceMs = this.form.options.listeners?.onChangeDebounceMs
     if (formDebounceMs && formDebounceMs > 0) {
       if (this.timeoutIds.formListeners.change) {

packages/form-core/src/FormApi.ts

@@ -870,6 +870,11 @@ export type AnyFormApi = FormApi<
   any
 >
 
+/**
+ * We cannot use methods and must use arrow functions. Otherwise, our React adapters
+ * will break due to loss of the method when using spread.
+ */
+
 /**
  * A class representing the Form API. It handles the logic and interactions with the form state.
  *
@@ -2016,12 +2021,17 @@ export class FormApi<
     return this.validateAsync(cause)
   }
 
+  // Needs to edgecase in the React adapter specifically to avoid type errors
+  handleSubmit(): Promise<void>
+  handleSubmit(submitMeta: TSubmitMeta): Promise<void>
+  handleSubmit(submitMeta?: TSubmitMeta): Promise<void> {
+    return this._handleSubmit(submitMeta)
+  }
+
   /**
    * Handles the form submission, performs validation, and calls the appropriate onSubmit or onSubmitInvalid callbacks.
    */
-  handleSubmit(): Promise<void>
-  handleSubmit(submitMeta: TSubmitMeta): Promise<void>
-  async handleSubmit(submitMeta?: TSubmitMeta): Promise<void> {
+  _handleSubmit = async (submitMeta?: TSubmitMeta): Promise<void> => {
     this.baseStore.setState((old) => ({
       ...old,
       // Submission attempts mark the form as not submitted
@@ -2539,7 +2549,7 @@ export class FormApi<
   /**
    * Updates the form's errorMap
    */
-  setErrorMap(
+  setErrorMap = (
     errorMap: FormValidationErrorMap<
       TFormData,
       UnwrapFormValidateOrFn<TOnMount>,
@@ -2553,7 +2563,7 @@ export class FormApi<
       UnwrapFormAsyncValidateOrFn<TOnDynamicAsync>,
       UnwrapFormAsyncValidateOrFn<TOnServer>
     >,
-  ) {
+  ) => {
     batch(() => {
       Object.entries(errorMap).forEach(([key, value]) => {
         const errorMapKey = key as ValidationErrorMapKeys

packages/react-form/src/useForm.tsx

@@ -226,6 +226,9 @@ export function useForm<
       TSubmitMeta
     > = {
       ...formApi,
+      handleSubmit: ((...props: never[]) => {
+        formApi._handleSubmit(...props)
+      }) as typeof formApi.handleSubmit,
       // We must add all `get`ters from `core`'s `FormApi` here, as otherwise the spread operator won't catch those
       get formId(): string {
         return formApi._formId