If you are a React developer and want to build your React apps faster and more robustly, this course is for you. Learn to integrate TypeScript with React, boost your productivity, and create apps that are easier to maintain.

In this course, you will learn how to utilize TypeScript’s sophisticated type system to make React development faster and your code more readable. You will learn how to create component props, state, and events that are strongly-typed, allowing you to quickly understand what you can pass and helping you avoid mistakes.

Lastly, you will set up React projects with TypeScript. First, you will learn how to do this with the Create React App tool, then how to create a React and TypeScript project with Webpack and Babel.

Using TypeScript with React

Nothing is wrong with this implemenation.

The type of the value for the context will be inferred as `any`. We can explicitly define the type for the context to create as follows:

```
const AuthContext = React.createContext<AuthContextType>(undefined);
```

The type of the value for the context will be inferred as `any`. We can explicitly define the type for the context to create as follows:

```
const AuthContext = React.createContext<AuthContextType | undefined>(undefined);
```

We are implementing a context for authentication. What is wrong with the implementation below and how can this be corrected?

```
type AuthContextType = {
  isAuthenticated: boolean;
  userName?: string;
  signIn: (userName: string) => void;
  signOut: () => void;
};
const AuthContext = React.createContext(undefined);
```

We are implementing a context for authentication. What is wrong with the implementation below and how can this be corrected?
<pre><code>type AuthContextType = {
 isAuthenticated: boolean;
 userName?: string;
 signIn: (userName: string) =&gt; void;
 signOut: () =&gt; void;
};
const AuthContext = React.createContext(undefined);
</code></pre>

```
const useAuth = <AuthContextType>() => React.useContext(AuthContext);
```

```
const useAuth = () => React.useContext<AuthContextType>(AuthContext);
```

```
const useAuth = () => React.useContext(AuthContext);
```

If we have a context called `AuthContext` that is of type `AuthContextType | undefined`, how can we create a strongly-typed custom hook to get access to the context? 

If we have a context called <code>AuthContext</code> that is of type <code>AuthContextType | undefined</code>, how can we create a strongly-typed custom hook to get access to the context?

If we have a function component and need to access a context in the components JSX, which approaches could we use? (tick all that apply).

If we have a function component and need to access a context in the components JSX, which approaches could we use? (tick all that apply).

Explicitly define `context` property and its type in the class:

```
context: React.ContextType<typeof AuthContext>;
```

Use the following type assertion:
```
const isAuthenticated = this.context!.isAuthenticated as boolean;  
```

Use the following type assertion:
```
const isAuthenticated = <boolean>this.context!.isAuthenticated; 
```

We are implementing a class component and are accessing a context in its `componentDidMount` method as follows:

```
componentDidMount() {
  const isAuthenticated = this.context!.isAuthenticated;  
  ...
}
```

The type of `isAuthenticated` is `any`. How should we resolve this?
  

We are implementing a class component and are accessing a context in its <code>componentDidMount</code> method as follows:
<pre><code>componentDidMount() {
 const isAuthenticated = this.context!.isAuthenticated; 
 ...
}
</code></pre>
The type of <code>isAuthenticated</code> is <code>any</code>. How should we resolve this?

Creating strongly-typed context

Creating strongly-typed context

This quiz will test your knowledge on using React's context in a strongly typed manner in both function and class components.

Why TypeScript?

Using basic types

Creating types

Working with generic types

Creating strongly-typed function component props

Creating strongly-typed function component state

Creating strongly-typed class components

Creating strongly-typed component events and event handlers

Creating strongly-typed context

Creating strongly-typed refs

Creating React projects with TypeScript using Create React App

Creating a React and TypeScript project manually

Putting everything together

Quiz