Redux is a popular JavaScript library for managing state in web applications. It provides a predictable, centralized store for the application state and a set of principles for managing that state in a way that's easy to understand and maintain.

However, as your Redux-powered application grows in complexity, it can be easy for the codebase to become cluttered and difficult to navigate. In this post, we'll look at some best practices and tips for organizing your Redux code in a way that's easy to understand and maintain.

If you want to learn more about React Query, another option for data management in React applications, check out my blog post about React Query vs Redux.

Keep related code together

One key principle of good code organization is to keep related code together. In a Redux application, this means keeping all of the code related to a particular feature or slice of state in a single place.

For example, let's say you have a to-do list feature in your application. You might want to keep all of the code related to this feature in a single directory, with separate files for the action creators, reducers, and any other related code. This makes it easy to find and modify the code related to this feature without having to search through the entire codebase.

Use a consistent naming convention

Choosing a consistent naming convention is important for making your codebase easy to understand. There are a few different conventions you could use for naming your Redux-related code, but one popular choice is the "ducks" pattern.

Under the ducks pattern, you would define all of the code related to a particular feature in a single file, which would be named after that feature. For example, the file for the to-do list feature might be called todos.js. Within that file, you would define the action types, action creators, and reducer functions, all following a consistent naming convention.

Use action constants

Instead of using string literals for your action types, it's a good idea to define action constants. This helps to prevent typos and makes your code easier to refactor.

To define action constants, you can create a separate file called actionTypes.js and define your constants as follows:

export const ADD_TODO = 'ADD_TODO';
export const REMOVE_TODO = 'REMOVE_TODO';
export const TOGGLE_TODO = 'TOGGLE_TODO';

Then, in your action creators and reducer functions, you can import these constants and use them like this:

import { ADD_TODO, REMOVE_TODO, TOGGLE_TODO } from './actionTypes';


function addTodo(text) {
  return {
    type: ADD_TODO,
    text
  };
}


function todosReducer(state, action) {
  switch (action.type) {
    case ADD_TODO:
      // Add the todo to the state
      break;
    case REMOVE_TODO:
      // Remove the todo from the state
      break;
    case TOGGLE_TODO:
      // Toggle the todo's "completed" status
      break;
    default:
      return state;
  }
}

Use selectors to access specific pieces of state

In a Redux application, you'll often need to access specific pieces of state when rendering components or performing other tasks. Instead of accessing the state directly, it's a good idea to use selectors for this purpose.

Selectors are pure functions that take the state as an argument and return the specific piece of state that you need. By using selectors, you can decouple your components from the specific shape of the state tree, making it easier to refactor your code later if the state shape changes.

To define a selector, you can create a separate file called selectors.js and define your selector functions like this:

export function getVisibleTodos(state, filter) {
  switch (filter) {
    case 'all':
      return state.todos;
    case 'completed':
      return state.todos.filter(t => t.completed);
    case 'active':
      return state.todos.filter(t => !t.completed);
    default:
      throw new Error(`Unknown filter: ${filter}`);
  }
}

Then, in your components, you can import the selector and use it to retrieve the specific piece of state that you need. For example:

import { getVisibleTodos } from './selectors';


function TodoList({ todos, filter }) {
  return (
    <ul>
      {getVisibleTodos(todos, filter).map(todo => (
        <li key={todo.id}>{todo.text}</li>
      ))}
    </ul>
  );
}

Use middleware for async actions

If your application performs asynchronous tasks, such as making API calls or interacting with a database, you'll need to handle these tasks in your Redux code. One way to do this is by using middleware.

Middleware is a function that sits between the action dispatch and the reducer and allows you to modify or augment the action before it reaches the reducer. This is particularly useful for handling async actions, as it allows you to dispatch actions that signal the start and end of an async task and update the state accordingly.

There are several popular Redux middleware libraries that you can use, such as redux-thunk and redux-saga. These libraries provide utility functions that make it easy to handle async actions in your Redux code.

Consider using a tool like reselect for optimization

As your application grows in size and complexity, you may find that your selectors become expensive to compute, especially if you have a large or deeply nested state tree. To optimize the performance of your selectors, you can use a library like reselect.

Reselect is a library that allows you to define "memoized" selectors, which only recompute their results when the values of their dependencies change. This can help to significantly improve the performance of your Redux code, especially in large applications with many components that depend on the same piece of state.

By following these best practices and tips, you can help to keep your Redux code organized, easy to understand, and maintainable as your application grows in complexity.