fix(form-core): TanStack#1336 add optional chaining operator when dynamically retrieving an errorMap value.

Author: juanvilladev

packages/form-core/src/FieldApi.ts

@@ -1403,7 +1403,8 @@ export class FieldApi<
             fieldLevelError,
           })
 
-        if (field.state.meta.errorMap[errorMapKey] !== newErrorValue) {
+        // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+        if (field.state.meta.errorMap?.[errorMapKey] !== newErrorValue) {
           field.setMeta((prev) => ({
             ...prev,
             errorMap: {

packages/form-core/src/FormApi.ts

@@ -1339,7 +1339,8 @@ export class FormApi<
           }
         }
 
-        if (this.state.errorMap[errorMapKey] !== formError) {
+        // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+        if (this.state.errorMap?.[errorMapKey] !== formError) {
           this.baseStore.setState((prev) => ({
             ...prev,
             errorMap: {