In this chapter, you'll learn about one of the core features that React offers for global state management, how and when to use it in your application, and how to combine it with the useReducer hook.

At the end of this section, you would know how to leverage the ContextAPI in your projects for better efficiency.

What is Context API?

The Context API is a feature build into React that allows you to manage global state and share it across multiple components, without having to pass props down manually through every level of the component tree. the Context API offers a simpler, built-in solution to handle state in a more global or centralized way. It is particularly useful when several components need access to the same data, such as themes, user authentication status, or language preferences.

Without the Context API, managing global state can become cumbersome, especially if the data needs to be passed down through many layers of components. The Context API allows you to "lift" the state out of individual components and provide it globally, so any component can access it, regardless of how deep it is nested in the tree.

Key Concepts of the Context API

To fully understand how the Context API works, we need to break it down into a few key concepts:

1. Creating Context

To create a Context in React, you use the React.createContext() function. This function returns an object with two components: a Provider and a Consumer. The Provider is used to provide the value to all child components that need access to the context.While, the Consumer allows components to subscribe to the context and access its value.

This is the basic syntax of creating a context:

const MyContext = React.createContext();

2. Provider

The Provider is a React component that accepts a value prop, which is the data or state you want to make available to the rest of your application.

Here's how to use a Provider in context:

<MyContext.Provider value={/* some value */}>
  <App />
</MyContext.Provider>

In the above example, value could be any JavaScript value (object, array, string, etc.) that will be passed to all child components that consume the context.

3. useContext Hook

This hook allows you to access context data or value in any component that needs it. It provides a simple syntax and makes the code readable.

This is the syntax of the useContext Hook:

const value = useContext(MyContext);

In this code example, the useContext hook retrieves the current value of MyContext allowing the component to access shared context data.

In the next lesson, we'll be learning how to use the Context API with the useContext hook to globally access values.