How do I use hooks in TypeScript?

How do I use hooks in TypeScript?

You can use hooks in TypeScript by defining your component with TypeScript types. For example, use useState like this: const [count, setCount] = useState<number>(0);.

Can you give me an example of a custom hook?

Sure! Here's a simple custom hook that fetches data:

import { useState, useEffect } from 'react';

function useFetch(url: string) {
    const [data, setData] = useState(null);
    const [loading, setLoading] = useState(true);

    useEffect(() => {
        fetch(url)
            .then(response => response.json())
            .then(data => {
                setData(data);
                setLoading(false);
            });
    }, [url]);

    return { data, loading };
}

How do I type the return value of my custom hook?

You can define an interface for the return value. For example:

interface UseFetchReturn<T> {
    data: T | null;
    loading: boolean;
}

function useFetch<T>(url: string): UseFetchReturn<T> {
    // implementation
}

What are some common pitfalls when using hooks in TypeScript?

Common pitfalls include not properly typing state and effects, and forgetting to include dependencies in the dependency array of useEffect.