[TypeScript] Fix withLifecycleCallback return type for augmented data providers

Author: fzaninotto

packages/ra-core/src/dataProvider/withLifecycleCallbacks.spec.ts

@@ -52,6 +52,21 @@ describe('withLifecycleCallbacks', () => {
         dataProvider.getMany('posts', { ids: [1, 2] });
         expect(resourceCallback.beforeGetMany).toHaveBeenCalled();
     });
+    it('should return the right type for augmented Data Providers', async () => {
+        const dataProvider = withLifecycleCallbacks(
+            {
+                ...testDataProvider(),
+                getFoo: async () => 'foo',
+            },
+            [
+                {
+                    resource: 'posts',
+                    beforeGetOne: jest.fn(params => Promise.resolve(params)),
+                },
+            ]
+        );
+        expect(dataProvider.getFoo).toBeDefined();
+    });
 
     describe('beforeGetList', () => {
         it('should update the getList parameters', async () => {

packages/ra-core/src/dataProvider/withLifecycleCallbacks.ts

@@ -119,10 +119,10 @@ import {
  *   ]
  * );
  */
-export const withLifecycleCallbacks = (
-    dataProvider: DataProvider,
+export const withLifecycleCallbacks = <T extends DataProvider = DataProvider>(
+    dataProvider: T,
     handlers: ResourceCallbacks[]
-): DataProvider => {
+): T => {
     return {
         ...dataProvider,