fix linter error and simplify return types

Author: slax57

packages/ra-core/src/form/validation/getSimpleValidationResolver.ts

@@ -1,4 +1,4 @@
-import { FieldValues, useForm } from 'react-hook-form';
+import { FieldValues } from 'react-hook-form';
 
 /**
  * Convert a simple validation function that returns an object matching the form shape with errors
@@ -31,7 +31,7 @@ export const getSimpleValidationResolver =
 
         // If there are no errors, early return the form values
         if (!errors || isEmptyObject(errors)) {
-            return { values: data as TFieldValues, errors: {} };
+            return { values: data, errors: {} };
         }
 
         // Else, we return an error object shaped like errors but having for each leaf
@@ -43,12 +43,12 @@ export const getSimpleValidationResolver =
         //   e.g. with an ArrayInput we can get something like: `{backlinks: [{}, {}]}`
         // If, after transformation, there are no errors, we return the form values
         if (!transformedErrors || isEmptyObject(transformedErrors)) {
-            return { values: data as TFieldValues, errors: {} };
+            return { values: data, errors: {} };
         }
 
         // Else return the errors and no values
         return {
-            values: {} as TFieldValues,
+            values: {},
             errors: transformedErrors,
         };
     };
@@ -111,4 +111,4 @@ export type ValidateForm<TFieldValues extends FieldValues = FieldValues> = (
 ) =>
     | Partial<Record<keyof TFieldValues, any>>
     | undefined
-    | Promise<Partial<Record<keyof TFieldValues, any>>>;
+    | Promise<Partial<Record<keyof TFieldValues, any>> | undefined>;