Function replaceReducer

src/createStore.ts:321–337

* Replaces the reducer currently used by the store to calculate the state. * * You might need this if your app implements code splitting and you want to * load some of the reducers dynamically. You might also need this if you * implement a hot reloading mechanism for Redux. * * @pa

(nextReducer: Reducer<S, A>)

   * @param nextReducer The reducer for the store to use instead.
   */
  function replaceReducer(nextReducer: Reducer<S, A>): void {
    if (typeof nextReducer !== 'function') {
      throw new Error(
        `Expected the nextReducer to be a function. Instead, received: '${kindOf(
          nextReducer
        )}`
      )
    }

    currentReducer = nextReducer as unknown as Reducer<S, A, PreloadedState>

    // This action has a similar effect to ActionTypes.INIT.
    // Any reducers that existed in both the new and old rootReducer
    // will receive the previous state. This effectively populates
    // the new state tree with any relevant data from the old one.
    dispatch({ type: ActionTypes.REPLACE } as A)
  }

  /**
   * Interoperability point for observable/reactive libraries.