fix: meta should not regenerate every render

docs/reference/classes/formapi.md

@@ -119,7 +119,7 @@ Defined in: [packages/form-core/src/FormApi.ts:377](https://github.com/TanStack/
 deleteField<TField>(field): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1182](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1182)
+Defined in: [packages/form-core/src/FormApi.ts:1194](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1194)
 
 #### Type Parameters
 
@@ -143,7 +143,7 @@ Defined in: [packages/form-core/src/FormApi.ts:1182](https://github.com/TanStack
 getFieldInfo<TField>(field): FieldInfo<TFormData, TFormValidator>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1091](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1091)
+Defined in: [packages/form-core/src/FormApi.ts:1103](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1103)
 
 Gets the field info of the specified field.
 
@@ -169,7 +169,7 @@ Gets the field info of the specified field.
 getFieldMeta<TField>(field): undefined | FieldMeta
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1082](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1082)
+Defined in: [packages/form-core/src/FormApi.ts:1094](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1094)
 
 Gets the metadata of the specified field.
 
@@ -195,7 +195,7 @@ Gets the metadata of the specified field.
 getFieldValue<TField>(field): DeepValue<TFormData, TField, IsNullable<TFormData>>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1075](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1075)
+Defined in: [packages/form-core/src/FormApi.ts:1087](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1087)
 
 Gets the value of the specified field.
 
@@ -221,7 +221,7 @@ Gets the value of the specified field.
 handleSubmit(): Promise<void>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1016](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1016)
+Defined in: [packages/form-core/src/FormApi.ts:1028](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1028)
 
 Handles the form submission, performs validation, and calls the appropriate onSubmit or onInvalidSubmit callbacks.
 
@@ -241,7 +241,7 @@ insertFieldValue<TField>(
 opts?): Promise<void>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1214](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1214)
+Defined in: [packages/form-core/src/FormApi.ts:1226](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1226)
 
 Inserts a value into an array field at the specified index, shifting the subsequent values to the right.
 
@@ -279,7 +279,7 @@ Inserts a value into an array field at the specified index, shifting the subsequ
 mount(): () => void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:595](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L595)
+Defined in: [packages/form-core/src/FormApi.ts:607](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L607)
 
 #### Returns
 
@@ -301,7 +301,7 @@ moveFieldValues<TField>(
    opts?): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1332](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1332)
+Defined in: [packages/form-core/src/FormApi.ts:1344](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1344)
 
 Moves the value at the first specified index to the second specified index within an array field.
 
@@ -342,7 +342,7 @@ pushFieldValue<TField>(
    opts?): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1196](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1196)
+Defined in: [packages/form-core/src/FormApi.ts:1208](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1208)
 
 Pushes a value into an array field.
 
@@ -379,7 +379,7 @@ removeFieldValue<TField>(
 opts?): Promise<void>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1267](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1267)
+Defined in: [packages/form-core/src/FormApi.ts:1279](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1279)
 
 Removes a value from an array field at the specified index.
 
@@ -417,7 +417,7 @@ replaceFieldValue<TField>(
 opts?): Promise<void>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1241](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1241)
+Defined in: [packages/form-core/src/FormApi.ts:1253](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1253)
 
 Replaces a value into an array field at the specified index.
 
@@ -455,7 +455,7 @@ Replaces a value into an array field at the specified index.
 reset(values?, opts?): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:656](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L656)
+Defined in: [packages/form-core/src/FormApi.ts:668](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L668)
 
 Resets the form state to the default values.
 If values are provided, the form will be reset to those values instead and the default values will be updated.
@@ -488,7 +488,7 @@ Optional options to control the reset behavior.
 resetFieldMeta<TField>(fieldMeta): Record<TField, FieldMeta>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1128](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1128)
+Defined in: [packages/form-core/src/FormApi.ts:1140](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1140)
 
 #### Type Parameters
 
@@ -512,7 +512,7 @@ Defined in: [packages/form-core/src/FormApi.ts:1128](https://github.com/TanStack
 setErrorMap(errorMap): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1356](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1356)
+Defined in: [packages/form-core/src/FormApi.ts:1368](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1368)
 
 Updates the form's errorMap
 
@@ -534,7 +534,7 @@ Updates the form's errorMap
 setFieldMeta<TField>(field, updater): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1110](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1110)
+Defined in: [packages/form-core/src/FormApi.ts:1122](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1122)
 
 Updates the metadata of the specified field.
 
@@ -567,7 +567,7 @@ setFieldValue<TField>(
    opts?): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1152](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1152)
+Defined in: [packages/form-core/src/FormApi.ts:1164](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1164)
 
 Sets the value of the specified field and optionally updates the touched state.
 
@@ -605,7 +605,7 @@ swapFieldValues<TField>(
    opts?): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:1306](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1306)
+Defined in: [packages/form-core/src/FormApi.ts:1318](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L1318)
 
 Swaps the values at the specified indices within an array field.
 
@@ -643,7 +643,7 @@ Swaps the values at the specified indices within an array field.
 update(options?): void
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:612](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L612)
+Defined in: [packages/form-core/src/FormApi.ts:624](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L624)
 
 Updates the form options and form state.
 
@@ -665,7 +665,7 @@ Updates the form options and form state.
 validateAllFields(cause): Promise<ValidationError[]>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:682](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L682)
+Defined in: [packages/form-core/src/FormApi.ts:694](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L694)
 
 Validates form and all fields in using the correct handlers for a given validation cause.
 
@@ -690,7 +690,7 @@ validateArrayFieldsStartingFrom<TField>(
 cause): Promise<ValidationError[]>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:710](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L710)
+Defined in: [packages/form-core/src/FormApi.ts:722](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L722)
 
 Validates the children of a specified array in the form starting from a given index until the end using the correct handlers for a given validation type.
 
@@ -726,7 +726,7 @@ validateField<TField>(field, cause):
 | Promise<ValidationError[]>
 ```
 
-Defined in: [packages/form-core/src/FormApi.ts:749](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L749)
+Defined in: [packages/form-core/src/FormApi.ts:761](https://github.com/TanStack/form/blob/main/packages/form-core/src/FormApi.ts#L761)
 
 Validates a specified field in the form using the correct handlers for a given validation type.
 

packages/form-core/src/FormApi.ts

@@ -416,8 +416,10 @@ export class FormApi<
             fieldName as never
           ] as FieldMetaBase | undefined
 
-          let fieldErrors =
-            prevVal?.[fieldName as never as keyof typeof prevVal]?.errors
+          const prevFieldInfo =
+            prevVal?.[fieldName as never as keyof typeof prevVal]
+
+          let fieldErrors = prevFieldInfo?.errors
           if (!prevBaseVal || currBaseVal.errorMap !== prevBaseVal.errorMap) {
             // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
             fieldErrors = Object.values(currBaseVal.errorMap ?? {}).filter(
@@ -428,6 +430,16 @@ export class FormApi<
           // As a primitive, we don't need to aggressively persist the same referencial value for performance reasons
           const isFieldPristine = !currBaseVal.isDirty
 
+          if (
+            prevFieldInfo &&
+            prevFieldInfo.isPristine === isFieldPristine &&
+            prevFieldInfo.errors === fieldErrors &&
+            currBaseVal === prevBaseVal
+          ) {
+            fieldMeta[fieldName] = prevFieldInfo
+            continue
+          }
+
           fieldMeta[fieldName] = {
             ...currBaseVal,
             errors: fieldErrors,

packages/react-form/tests/useField.test.tsx

@@ -1,3 +1,4 @@
+/* eslint-disable react-compiler/react-compiler */
 import { describe, expect, it, vi } from 'vitest'
 import { render, waitFor } from '@testing-library/react'
 import { userEvent } from '@testing-library/user-event'
@@ -1068,4 +1069,65 @@ describe('useField', () => {
     await user.click(getByText('Add person'))
     expect(getByText(`["Test"]`)).toBeInTheDocument()
   })
+
+  it('should not rerender unrelated fields', async () => {
+    const renderCount = {
+      field1: 0,
+      field2: 0,
+    }
+
+    function Comp() {
+      const form = useForm({
+        defaultValues: {
+          field1: '',
+          field2: '',
+        },
+      })
+
+      return (
+        <>
+          <form.Field name="field1">
+            {(field) => {
+              renderCount.field1++
+              return (
+                <input
+                  data-testid="field1"
+                  value={field.state.value}
+                  onChange={(e) => field.handleChange(e.target.value)}
+                />
+              )
+            }}
+          </form.Field>
+          <form.Field name="field2">
+            {(field) => {
+              renderCount.field2++
+              return (
+                <input
+                  data-testid="field2"
+                  value={field.state.value}
+                  onChange={(e) => field.handleChange(e.target.value)}
+                />
+              )
+            }}
+          </form.Field>
+        </>
+      )
+    }
+
+    const { getByTestId } = render(
+      <StrictMode>
+        <Comp />
+      </StrictMode>,
+    )
+
+    const field1InitialRender = renderCount.field1
+    const field2InitialRender = renderCount.field2
+
+    await user.type(getByTestId('field1'), 'test')
+
+    // field1 should have rerendered
+    expect(renderCount.field1).toBeGreaterThan(field1InitialRender)
+    // field2 should not have rerendered
+    expect(renderCount.field2).toBe(field2InitialRender)
+  })
 })