feat(core): add form listners for reset

Author: harry-whorlow

.changeset/reset-listeners.md

@@ -0,0 +1,5 @@
+---
+"@tanstack/form-core": minor
+---
+
+Add `onReset` listener support for forms and fields, add `reset` method to `FieldApi`, and expand `ListenerCause` type with `'reset'` and `'unmount'` values

packages/form-core/src/FieldApi.ts

@@ -8,8 +8,10 @@ import {
   determineFieldLevelErrorSourceAndValue,
   evaluate,
   getAsyncValidatorArray,
+  getBy,
   getSyncValidatorArray,
   mergeOpts,
+  setBy,
 } from './utils'
 import { defaultValidationLogic } from './ValidationLogic'
 import type { ReadonlyStore } from '@tanstack/store'
@@ -384,6 +386,7 @@ export interface FieldListeners<
   onMount?: FieldListenerFn<TParentData, TName, TData>
   onUnmount?: FieldListenerFn<TParentData, TName, TData>
   onSubmit?: FieldListenerFn<TParentData, TName, TData>
+  onReset?: FieldListenerFn<TParentData, TName, TData>
 }
 
 /**
@@ -2090,6 +2093,17 @@ export class FieldApi<
     )
   }
 
+  /**
+   * Resets the field value and meta to default state.
+   */
+  reset = () => {
+    this.form.resetField(this.name)
+    this.options.listeners?.onReset?.({
+      value: this.state.value,
+      fieldApi: this,
+    })
+  }
+
   private triggerOnBlurListener() {
     const formDebounceMs = this.form.options.listeners?.onBlurDebounceMs
     if (formDebounceMs && formDebounceMs > 0) {

packages/form-core/src/FormApi.ts

@@ -324,6 +324,23 @@ export interface FormListeners<
     >
     fieldApi: AnyFieldApi
   }) => void
+
+  onReset?: (props: {
+    formApi: FormApi<
+      TFormData,
+      TOnMount,
+      TOnChange,
+      TOnChangeAsync,
+      TOnBlur,
+      TOnBlurAsync,
+      TOnSubmit,
+      TOnSubmitAsync,
+      TOnDynamic,
+      TOnDynamicAsync,
+      TOnServer,
+      TSubmitMeta
+    >
+  }) => void
 }
 
 /**
@@ -1541,6 +1558,8 @@ export class FormApi<
         fieldMetaBase,
       }),
     )
+
+    this.options.listeners?.onReset?.({ formApi: this })
   }
 
   /**

packages/form-core/src/types.ts

@@ -21,7 +21,13 @@ export type ValidationCause =
 /**
  * @private
  */
-export type ListenerCause = 'change' | 'blur' | 'submit' | 'mount'
+export type ListenerCause =
+  | 'change'
+  | 'blur'
+  | 'submit'
+  | 'mount'
+  | 'reset'
+  | 'unmount'
 
 /**
  * @private