title: Lazy Loading Redux Toolkit Slices date: 2021-10-15 tags: lazy-loading, Redux Toolkit —

Lazy loading is a technique often used in web development to optimize the loading time of web applications. It allows for the on-demand loading of resources, thus reducing the initial load time. When working with Redux Toolkit, lazy loading can also be applied to the slices to improve performance.

What are Redux Toolkit Slices?

Redux Toolkit is a library that provides a set of utilities and conventions to simplify the implementation of Redux in your application. It includes a feature called slices, which are small, self-contained units of Redux logic that handle a specific portion of the application state.

Slices define the Redux actions and reducers needed to manage a specific part of the state. They enable modular code organization, making it easier to reason about and maintain your Redux store.

Why Lazy Load Redux Toolkit Slices?

As your application grows, the number of slices and their associated logic might increase. Loading all the slices upfront can result in a larger bundle size and slower initial load times.

By lazy loading the slices, you can delay the loading of specific Redux logic until it is actually needed. This allows for a more efficient usage of resources and faster initial load times, especially for less frequently accessed parts of your application.

How to Lazy Load Redux Toolkit Slices?

To lazy load Redux Toolkit slices, you can utilize dynamic imports in your code. Dynamic imports allow you to load modules on-demand, instead of including them in the main bundle.

Here’s an example of how you can lazy load a Redux Toolkit slice:

import { createAsyncThunk, createSlice } from '@reduxjs/toolkit';

const fetchUser = createAsyncThunk('users/fetchUser', async (userId) => {
  const response = await fetch(`/api/users/${userId}`);
  const data = await response.json();
  return data;
});

const userSlice = createSlice({
  name: 'users',
  initialState: { users: [] },
  reducers: {},
  extraReducers: (builder) => {
    builder.addCase(fetchUser.fulfilled, (state, action) => {
      state.users.push(action.payload);
    });
  },
});

export const { reducer } = userSlice;
export const { fetchUser } = userSlice.actions;

export default userSlice;

By dynamically importing this module when needed, you can control when the slice is loaded into your Redux store.

import { lazy } from 'react';

const LazyUserSlice = lazy(() => import('./userSlice'));

// Then, use `LazyUserSlice.reducer` and `LazyUserSlice.fetchUser` in your Redux store

Conclusion

Lazy loading Redux Toolkit slices can significantly improve the performance and loading time of your web application. By loading only the necessary Redux logic, you can optimize the initial load time and make your application more efficient.

Consider incorporating lazy loading techniques into your Redux Toolkit implementation to achieve a better user experience and faster load times.