`useContext` is a hook in the React Context API that allows you to consume the context value in a functional component. It works by taking a context object as an argument and returning the current context value for that context.

Here's an example of how you might use `useContext` to consume the context value in a functional component:

```javascript
import React, { useContext } from 'react';

// Create the context object
const ThemeContext = React.createContext('light');

// Create a provider component
class ThemeProvider extends React.Component {
  state = { theme: 'light' };

  toggleTheme = () => {
    this.setState(state => ({
      theme: state.theme === 'light' ? 'dark' : 'light'
    }));
  };

  render() {
    return (
      // Provide the theme value to the component tree
      <ThemeContext.Provider value={{ theme: this.state.theme, toggleTheme: this.toggleTheme }}>
        {this.props.children}
      </ThemeContext.Provider>
    );
  }
}

// Create a functional component that consumes the theme value
const ThemeTogglerButton = () => {
  // Use the useContext hook to consume the theme value
  const { theme, toggleTheme } = useContext(ThemeContext);

  return (
    <button onClick={toggleTheme} style={{ backgroundColor: theme === 'light' ? 'white' : 'black' }}>
      Toggle Theme
    </button>
  );
};

const App = () => (
  <ThemeProvider>
    <ThemeTogglerButton />
  </ThemeProvider>
);
```

In this example, the `ThemeTogglerButton` functional component is able to consume the `theme` and `toggleTheme` values from the `ThemeContext` without having to pass them down as props. It does this by using the `useContext` hook and passing the `ThemeContext` object as an argument. The hook returns the current context value for the `ThemeContext`, which can then be destructured and used within the component.

One advantage of using `useContext` is that it allows you to avoid the nesting and rendering overhead of the `Consumer` component. This can make your code simpler and more performant, especially if you have a deeply nested component tree that needs to access the context value.



How is a context object created in the react-context API?

When should the useContext hook be used in the react-context API?

When should you use the Context API instead of props for sharing state?

What is the createContext function used for in the Context API?

React is a popular JavaScript library for building user interfaces. It is developed and maintained by Facebook and is used by many large companies to create complex and interactive web and mobile applications. quckReact uses a virtual DOM to update the user interface efficiently and uses a declarative approach to programming, making it easy to reason about and predict the behavior of an application. React is known for its efficiency and flexibility and allows developers to create reusable components that can be quickly composed to build complex user interfaces.

The prompt provides a list of terms that are commonly used in React, a popular JavaScript library for building user interfaces. The terms include React, component, virtual DOM, JSX, constructor() method, render() method, state, setState() method, props, and binding methods. The prompt does not provide any additional context or information about these terms.

Now that we have become familiar with most of the React basics and how components work and integrate into the development of a website. Since we know that React components are loaded onto the main page and then can be dynamically updated which means that they go through a certain cycle of stages that can be intervened in and the behavior can be updated. 

This cycle can be manipulated through what are called lifecycle functions at different stages. React class component lifecycle methods are used for a variety of purposes, including performing setup tasks when a component is first rendered, updating a component in response to changes in props or state, and cleaning up any resources that the component is using.

Now that we have gone over the basics of class-based components, we will now explore a better and more concise way to write React components with functional components which are a lot more commonly used in React these days.

Functional components are a way to define components in React that are simple, lightweight, and only consist of a render function. They are a great choice for simple, presentational components that only need to render some JSX and don't have their own state or lifecycle methods.

In this section of the course, we'll look at how to use functional components with Hooks to manage state and other lifecycle events.

Now, we understand the basics of React with regards to the various kinds of components available and how to use them and exploit their lifecycle to our advantage in a webpage, we will now move on to some advanced topics. These topics will deal with topics like state management through Context API and the Consumer and Provider architecture in React and how these things make life easier in a production-level React App.

Then we will move onto Routing in react and how it all works to produce a navigable React App without having to reload the page. This involves studying an important React package called “react-router-dom” which we will get into in this section.

React Tutorial

useContext()

1. How is a context object created in the react-context API?

2. When should the useContext hook be used in the react-context API?

3. Fill in the given code:

4. When should you use the Context API instead of props for sharing state?

5. What is the createContext function used for in the Context API?