Optimizing Performance for Large State Trees

Provide an example of optimizing a createReducer function that handles a large and complex state tree, focusing on targeted state updates to prevent unnecessary processing.
import { createReducer } from '@reduxjs/toolkit';
import { updateSpecificKey } from './nestedStateHelpers';

// Define the initial state with a large and complex state tree
const initialState = {
    // Large and complex structure
    data: {
        // Nested structure ...
    // More state keys ...

// Reducer function optimized for targeted updates
const complexStateReducer = createReducer(initialState, {
    // Optimize updating deeply nested values
    'UPDATE_DEEP_NESTED_FIELD': (state, action) => {
        const { path, value } = action.payload;
        updateSpecificKey(, path, value);
    // Other cases handling multiple state updates efficiently
    // ...

function updateDeepNestedField(path, value) {
    return {
        payload: { path, value }
This example demonstrates how to use Redux Toolkit's createReducer with targeted state updates for a large and complex state tree. Instead of spreading the entire state object in the reducer, we use a utility function (updateSpecificKey) to update only the deeply nested value efficiently. This approach minimizes the performance impact of handling a large state tree by avoiding unnecessary updates to the rest of the state.