Discover how React Tracked optimizes render performance in web apps. Build a to-do app using two methods, and gain skills to create advanced applications efficiently.

React Tracked is a small library for global state with React Hooks and
React Context. It allows you to develop a small web app with global state
without a bigger library like Redux.

In this course, you will create a to-do app. But before diving into
creating an application, you’ll first learn how React Tracked can solve
common performance issues around render optimization. Once you learn how to
work with this library, you’ll then build a to-do app through two different
methods.

By the end of this course, you will be ready to build more advanced
applications without having to do unnecessary re-rendering. You’ll also
have a nice piece to showcase in your portfolio.

React Tracked: Creating Web Apps with Global State

# App

This is the root component that wraps the TodoList in the Provider.

```javascript
// ./components/App.js

import React from 'react';

import { Provider } from './store';
import TodoList from './TodoList';

const App = () => (
  <Provider>
    <TodoList />
  </Provider>
);

export default App;
```
# Utils

We have one more file that exports `useFlasher`.

```javascript
// ./utils.js

import { useEffect, useRef } from 'react';
 
export const useFlasher = () => {
  const ref = useRef(null);
  useEffect(() => {
    ref.current.classList.add('flash');
    setTimeout(() => {
      ref.current.classList.remove('flash');
    }, 300);
  });
  return ref;
};
```

# Folder structure

Our files are stored in different directories. Below is a list of all the files:

```
store.js
hooks/useTodoList.js
hooks/useAddTodo.js
hooks/useDeleteTodo.js
hooks/useToogleTodo.js
hooks/useQuery.js
components/TodoList.js
components/TodoItem.js
components/NewTodo.js
components/App.js
utils.js
```

# Next

In the next lesson, we check the app behavior with a working demo.

In this lesson, we create an App component.

Creating a Counter App only with React Context

Introducing React Tracked to the Counter App

Developing ToDo App with React Tracked and useReducer

Developing ToDo App with React Tracked, useState and Immer

Going Further

App Component and File Structure

App