Allow mutating registry reducers in types

Author: JackWilb

packages/core/src/registry/action.ts

@@ -11,13 +11,12 @@ export type TrrackActionFunction<
     undo: PayloadAction<UndoActionPayload, UndoActionType>;
 };
 
-export type ProduceWrappedStateChangeFunction<T> = (state: T, args: any) => T
+export type ProduceWrappedStateChangeFunction<T> = (state: T, args: any) => T;
 
 export type StateChangeFunction<State, Payload> = (
     state: State,
     payload: Payload
-) => ReturnType<ProduceWrappedStateChangeFunction<State>>;
-
+) => void | ReturnType<ProduceWrappedStateChangeFunction<State>>;
 
 export type Label = string;
 export type LabelGenerator<Args> = (args: Args) => Label;

packages/core/src/registry/reg.spec.ts

@@ -20,7 +20,6 @@ describe('Registry', () => {
             'add',
             (state: { count: number }, amount: number) => {
                 state.count += amount;
-                return state;
             }
         );