How I structure my React projects

This post was originally published on my blog.

It's been quite a while since I wrote an article about how I structure my Node.js REST APIs. The article covered the approach of designing a well organized and maintainable folder structure for Node.js applications.

So today I don't want to talk about Node.js APIs, but about the architecture of React applications and answer the same question from the previous article a second time:

What should the folder structure look like?

And again: there’s no perfect or 100% correct answer to this question, but there are tons of other articles discussing this one on the internet too. This folder structure is also partly based on multiple of them.

One important thing to mention is that React does not really tell you how to organize your project, except the fact that you should avoid too much nesting and overthinking. To be exact they say: (Source)

React doesn’t have opinions on how you put files into folders. That said there are a few common approaches popular in the ecosystem you may want to consider.

Take a look at the linked source where you can read more about those common approaches. They won't be further discussed in this article.

The following structure and architecture is one that has proven maintainable and reliable for me. It might give you a help for designing your own project. Keep in mind that the following architecture is based on a application bootstrapped with create-react-app and written in JavaScript.

Directory: root

react-project
├── node_modules
├── public
├── src
├── package.json
└── package-lock.json

This structure is nothing special and shouldn’t be new to you. It’s actually a basic create-react-app setup. The interesting part here is the content of the src folder which this article is about.

So what do we have in here?

react-project
├── api
├── components
├── i18n
├── modules
├── pages
├── stores
├── tests
├── utils
├── index.js
├── main.js
└── style.css

As you can see the application is primarily split into eight directories. From here on, we'll go top-down through the directories and examine each one.

Let’s start with the api directory.

Directory: src/api

react-project
├── api
│   ├── services
│   │   ├── Job.js
│   │   ├── User.js
│   ├── auth.js
│   └── axios.js

The api directory contains all services that take care of the communication between the React application (frontend) and an API (backend). A single service provides multiple functions to retrieve data from or post data to an external service using the HTTP protocol.

auth.js provides functions for authentication and axios.js contains an axios instance including interceptors for the outgoing HTTP requests and incoming responses. Moreover, the process of refreshing JWTs is handled in here.

Directory: src/components

react-project
├── components
│   ├── Job
│   │   ├── Description.js
│   │   └── Preview.js
│   └── User
│   │   ├── Card.js
│   │   ├── Create.js
│   │   └── List.js

If you're already familiar with React you should know that it's mainly component based. The components are actually the heart of every React application. The whole application, at least the presentational view, is built of many small components.

So what is a component? Source

Components let you split the UI into independent, reusable pieces, and think about each piece in isolation.

Imagine you have a website like Twitter or Facebook. The large website is made of many smaller pieces (components) that can be Buttons, Inputs or Widgets for example. Those pieces are put together to build ever more complex and larger ones. Each component has its own lifecyle and state management, whereby you can share a component's state with other ones.

Components are reused multiple times within the application to save the developer from writing redundant code.

Don't repeat yourself (DRY)

Splitting the codebase into multiple components is not just a "React thing". It's a common pattern in software engineering to simplify the development process and the maintenance later on.

In React, a component is mostly a simple JavaScript function or a class. Usually, I create a new file for each single component. In some rare cases I group multiple of them (functions or classes) into a single file. Imagine a UserList.js component which renders multiple elements of UserListItem:

const UserList = ({ users }) => (
  <ul>
    {users.map(user => (
      <UserListItem key={user.userId} user={user} />
    ))}
  </ul>
)

const UserListItem = ({ user }) => <li>{user.name}</li>

Here, it makes sense to combine both into one file. Further, UserListItem is probably not even used by any other component than UserList.

Beside the components themselves, you can also add their stylesheets or tests to this directory.

Directory: src/i18n

react-project
├── i18n
│   ├── de.json
│   └── en.json

i18n stands for internationalization and takes care of the language support of the application. The including JSON files are basically objects containg fixed constants as keys and their associated translations as values.

Therefore, the keys should be equal for each language file. Only the values (translations) differ from each other. You can easily query those language files later on by writing your own custom hook or component.

Directory: src/modules

react-project
├── modules
│   ├── logger.js
│   └── session.js

This directory includes some global modules that might be used for logging or as wrapper for the browser's LocalStorage for example.

Directory: src/pages

react-project
├── pages
│   ├── Home
│   │   ├── components
│   │   │   ├── Dashboard.js
│   │   │   └── Welcome.js
│   │   └── index.js
│   ├── Login.js
│   └── Profile.js

The pages directory includes the react-router-dom paths accessed while navigating through the application. Here, we collect multiple components into a single larger one to display a complete page view.

A page might contain its own component directory which includes "local" components that are only used on this page. For complex pages with a deep component tree you might want to check out the React Context API which makes it much easier to pass props along the tree and to handle a global "page state".

Directory: src/stores

react-project
├── stores
│   ├── language.js
│   └── user.js

This directory includes all global React states that can be accessed from any component within the application. While Redux is probably the most popular solution for managing global state I prefer to use zustand. It's very easy to get started with and its API is really straightforward.

Directory: src/tests

react-project
├── tests
│   ├── language.test.js
│   └── utils.test.js

The tests directory includes tests that do not belong to certain components. This could be tests for the implementation of algorithms for example. Moreover, I validate and compare the keys of the language files I mentioned above to make sure I did not miss any translation for a given language.

Directory: src/utils

react-project
├── utils
│   ├── hooks
│   │   ├── useChat.js
│   │   ├── useOutsideAlerter.js
│   │   ├── useToast.js
│   ├── providers
│   │   ├── HomeContextProvider.js
│   │   ├── ToastContextProvider.js
│   ├── colors.js
│   ├── constants.js
│   ├── index.js

Here, we have a bunch of utilities like: custom hooks, context providers, constants and helper functions. Feel free to add more stuff here.

All together

Last but not least a complete overview of the project structure:

react-project
├── api
│   ├── services
│   │   ├── Job.js
│   │   ├── User.js
│   ├── auth.js
│   └── axios.js
├── components
│   ├── Job
│   │   ├── Description.js
│   │   └── Preview.js
│   └── User
│   │   ├── Card.js
│   │   ├── Create.js
│   │   └── List.js
├── i18n
│   ├── de.json
│   └── en.json
├── modules
│   ├── logger.js
│   └── session.js
├── pages
│   ├── Home
│   │   ├── components
│   │   │   ├── Dashboard.js
│   │   │   └── Welcome.js
│   │   └── index.js
│   ├── Login.js
│   └── Profile.js
├── stores
│   ├── language.js
│   └── user.js
├── tests
│   ├── language.test.js
│   └── utils.test.js
├── utils
│   ├── hooks
│   │   ├── useChat.js
│   │   ├── useOutsideAlerter.js
│   │   ├── useToast.js
│   ├── providers
│   │   ├── HomeContextProvider.js
│   │   ├── ToastContextProvider.js
│   ├── colors.js
│   ├── constants.js
│   ├── index.js
├── index.js
├── main.js
└── style.css

That’s it! I hope this is a little help for people who don't know how to structure their React application or didn’t know how to start. Feel free to give any suggestions.