fix(form-core): update pacer to pacer-lite

.changeset/sparkly-paths-sort.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/form-core': patch
+---
+
+Bump TanStack pacer to pacer-lite for reduced custom event emissions.

packages/form-core/package.json

@@ -52,7 +52,7 @@
   ],
   "dependencies": {
     "@tanstack/devtools-event-client": "^0.3.5",
-    "@tanstack/pacer": "^0.15.3",
+    "@tanstack/pacer-lite": "^0.1.1",
     "@tanstack/store": "^0.7.7"
   },
   "devDependencies": {

packages/form-core/src/FormApi.ts

@@ -1,5 +1,4 @@
 import { Derived, Store, batch } from '@tanstack/store'
-import { throttle } from '@tanstack/pacer'
 import {
   deleteBy,
   determineFormLevelErrorSourceAndValue,
@@ -12,16 +11,18 @@ import {
   isNonEmptyArray,
   mergeOpts,
   setBy,
+  throttleFormState,
   uuid,
 } from './utils'
 import { defaultValidationLogic } from './ValidationLogic'
-
 import {
   isStandardSchemaValidator,
   standardSchemaValidators,
 } from './standardSchemaValidator'
 import { defaultFieldMeta, metaHelper } from './metaHelper'
 import { formEventClient } from './EventClient'
+
+// types
 import type { ValidationLogicFn } from './ValidationLogic'
 import type {
   StandardSchemaV1,
@@ -1310,20 +1311,9 @@ export class FormApi<
 
     this.update(opts || {})
 
-    const debouncedDevtoolState = throttle(
-      (state: AnyFormState) =>
-        formEventClient.emit('form-state', {
-          id: this._formId,
-          state: state,
-        }),
-      {
-        wait: 300,
-      },
-    )
-
     // devtool broadcasts
     this.store.subscribe(() => {
-      debouncedDevtoolState(this.store.state)
+      throttleFormState(this)
     })
 
     // devtool requests

packages/form-core/src/utils.ts

@@ -1,7 +1,8 @@
-import { defaultValidationLogic } from './ValidationLogic'
+import { liteThrottle } from '@tanstack/pacer-lite'
+import { formEventClient } from './EventClient'
 import type { ValidationLogicProps } from './ValidationLogic'
 import type { FieldValidators } from './FieldApi'
-import type { FormValidators } from './FormApi'
+import type { AnyFormApi, FormValidators } from './FormApi'
 import type {
   GlobalFormValidationError,
   ValidationCause,
@@ -603,3 +604,14 @@ export function uuid(): string {
   IDX++
   return out
 }
+
+export const throttleFormState = liteThrottle(
+  (form: AnyFormApi) =>
+    formEventClient.emit('form-state', {
+      id: form.formId,
+      state: form.store.state,
+    }),
+  {
+    wait: 300,
+  },
+)