Answer by MilV for NGRX reducers using the same state object

This solutionSplitting big reducer into smaller reducersis not exactly to your question in grabbing the same state object.

here my solution that might be solvable:

export const mergeReducers = <TState>(...reducers: ActionReducer<TState>[]): ActionReducer<TState> => {  return (state: TState, action: Action) => {    if (reducers.length === 0) {      throw new Error('At least one reducer is required');    }    return reducers.reduce((initialState, reducer) => {      return reducer(initialState, action);    }, state);  };};