Notice: This page requires JavaScript to function properly.
Please enable JavaScript in your browser settings or update your browser.
Oppiskele Typing Functional Components | Typing React Components
Quizzes & Challenges
Quizzes
Challenges
/
TypeScript Essentials for React

bookTyping Functional Components

When working with React and TypeScript, it's important to type your functional components so TypeScript can catch mistakes before they reach the browser. Typing props makes your components predictable, safer, and easier to understand. The first step is to describe the structure of your props using either an interface or a type alias. This tells TypeScript exactly what values your component expects. Then, you apply that type to the component's props.

Here is a simple example of a typed functional component that receives a label prop:

type ButtonProps = {
  label: string;
};

function Button({ label }: ButtonProps) {
  return <button>{label}</button>;
}

In this version, the Button component accepts only one prop — a string called label. If you try to pass anything else (like a number), TypeScript will show an error during development. This helps you avoid common bugs and makes your code easier to maintain.

You can also specify the return type explicitly using JSX.Element, although TypeScript can usually infer it:

function Button({ label }: ButtonProps): JSX.Element {
  return <button>{label}</button>;
}

Key points to remember:

  • Define small, clear prop types with type or interface;
  • Type the props directly on the component function;
  • Rely on TypeScript to warn you about incorrect prop usage;
question mark

What is the purpose of typing functional components in React with TypeScript?

Select the correct answer

Oliko kaikki selvää?

Miten voimme parantaa sitä?

Kiitos palautteestasi!

Osio 2. Luku 1

Kysy tekoälyä

expand

Kysy tekoälyä

ChatGPT

Kysy mitä tahansa tai kokeile jotakin ehdotetuista kysymyksistä aloittaaksesi keskustelumme

Suggested prompts:

Can you show an example with multiple props?

What's the difference between using type and interface for props?

How do I make some props optional?

Awesome!

Completion rate improved to 4.17

bookTyping Functional Components

Pyyhkäise näyttääksesi valikon

When working with React and TypeScript, it's important to type your functional components so TypeScript can catch mistakes before they reach the browser. Typing props makes your components predictable, safer, and easier to understand. The first step is to describe the structure of your props using either an interface or a type alias. This tells TypeScript exactly what values your component expects. Then, you apply that type to the component's props.

Here is a simple example of a typed functional component that receives a label prop:

type ButtonProps = {
  label: string;
};

function Button({ label }: ButtonProps) {
  return <button>{label}</button>;
}

In this version, the Button component accepts only one prop — a string called label. If you try to pass anything else (like a number), TypeScript will show an error during development. This helps you avoid common bugs and makes your code easier to maintain.

You can also specify the return type explicitly using JSX.Element, although TypeScript can usually infer it:

function Button({ label }: ButtonProps): JSX.Element {
  return <button>{label}</button>;
}

Key points to remember:

  • Define small, clear prop types with type or interface;
  • Type the props directly on the component function;
  • Rely on TypeScript to warn you about incorrect prop usage;
question mark

What is the purpose of typing functional components in React with TypeScript?

Select the correct answer

Oliko kaikki selvää?

Miten voimme parantaa sitä?

Kiitos palautteestasi!

Osio 2. Luku 1
some-alt