feat: provide parent state as second parameter to update function in wrapReducerWithFormStateUpdate

Author: MrWolfZ

src/reducer.spec.ts

@@ -237,6 +237,30 @@ describe(wrapReducerWithFormStateUpdate.name, () => {
     expect(resultState).toBe(initialState);
   });
 
+  it('should pass the state as the second parameter to the update function', () => {
+    const wrappedReducer = wrapReducerWithFormStateUpdate(reducer, s => s.control, (s, state) => {
+      expect(state).toBe(initialState);
+      return s;
+    });
+
+    wrappedReducer(undefined, { type: '' });
+  });
+
+  it('should call the update function after the reducer', () => {
+    let reducerWasCalled = false;
+    const reducer = (s = initialState) => {
+      reducerWasCalled = true;
+      return s;
+    };
+
+    const wrappedReducer = wrapReducerWithFormStateUpdate(reducer, s => s.group, s => {
+      expect(reducerWasCalled).toBe(true);
+      return s;
+    });
+
+    wrappedReducer(undefined, { type: '' });
+  });
+
   it('should work with createReducer', () => {
     const state = {
       prop: 'value',

src/reducer.ts

@@ -109,19 +109,22 @@ export function onNgrxForms<TState = any>(): { reducer: ActionReducer<TState>; t
  * This function wraps a reducer and returns another reducer that first calls
  * the given reducer and then calls the given update function for the form state
  * that is specified by the form state locator function.
+ *
+ * The update function is passed the form state and the updated containing state
+ * as parameters.
  */
 export function wrapReducerWithFormStateUpdate<TState, TFormState extends AbstractControlState<any>>(
   reducer: ActionReducer<TState>,
   formStateLocator: (state: TState) => TFormState,
-  updateFn: (formState: TFormState) => TFormState,
+  updateFn: (formState: TFormState, state: TState) => TFormState,
 ): ActionReducer<TState> {
   return (state, action) => {
     const updatedState = reducer(state, action);
 
     const formState = formStateLocator(updatedState);
     const formStateKey = Object.keys(updatedState).find(key => updatedState[key as keyof TState] as any === formState)!;
 
-    const updatedFormState = updateFn(formState);
+    const updatedFormState = updateFn(formState, updatedState);
 
     if (updatedFormState === formState) {
       return updatedState;