The use hook is a game changer for React

If you've worked with React before, there's a very good chance that you've needed to fetch some data from an external source. And with that, there's a very good chance that you've done your data fetching asynchronously and have shot yourself in the foot with useEffect.

Now, libraries like react-query and SWR help, but it would be nice if React was able to support promises out of the box. That's all about to change with a new RFC that was released. This RFC outlines a new hook to React that added first-class support for promises and async/await. Let's take a look at this new hook and talk about some of its implications!

Meet the use hook

The use hook, which is outlined in this RFC, lets us finally use async code in React, which means no more data fetching in a useEffect!

In our React code, we can use the use hook like so:

export async function fetchPokemon() {
 const pokemonResponse = await fetch('https://pokeapi.co/api/v2/pokemon?limit=150');

 return pokemonResponse.json(); // Returns a Promise
}

export default function PokemonList() {
 const pokemon = use(fetchPokemon);

 return (
  <ul>
   {pokemon.map(pokemon => (
    <li>{/* Normal react stuff */}</li>
   ))}
  </ul>
 );
}

It's that simple. No useEffect or external libraries are needed to do our data fetching.

Another cool thing with the use hook is that it can be used conditionally:

export async function fetchPokemon() {
 const [pokemon, setPokemon] = useState<Pokemon[] | null>(null);

 const generation = 1;

 if (generation === 1) {
  const fetchedPokemon = use(fetchPokemon);
  setPokemon(fetchedPokemon);
 }

 // Rest of the component
}

What does this mean for libraries like react-query and SWR?

The new use hook won't replace these libraries. The use hook, similar to await, is only for wrapping promises. Both react-query and SWR offer a lot of features on top of just making data fetching safer, including caching, retries, and so much more. Even when use is released, these libraries will most likely be the way to go for data fetching.

That being said, it will be interesting to see if/how these libraries introduce use into their code bases. It will be interesting to see what other new tools and libraries are created with use at its core. We'll also most likely be seeing new patterns emerge around this hook. For example, letting use be used conditionally is already a departure from other hooks. There's also a proposal in the RFC about being able to wrap React Context in a use hook. It does say that this feature could fall outside of the scope of this specific proposal and be implemented later on, but it would let you do things like use React Context conditionally.

Wrap up

To me, use is one of the coolest features coming to React and could fundamentally change how we build React apps. I'm excited to see how use gets used and the new patterns that emerge from it. This is a huge feature for not just React itself, but the entire ecosystem as a whole.

How do you feel about the use hook? Is this the right direction for React to go? I would love to hear your thoughts on it! You can connect with me on Twitter @BrockHerion or you can send me an email.