Multiple fetch data axios with React Hooks

问题

I would like to get global information from Github user and his repos(and get pinned repos will be awesome). I try to make it with async await but It's is correct? I've got 4 times reRender (4 times console log). It is possible to wait all component to reRender when all data is fetched?

function App() {
  const [data, setData] = useState(null);
  const [repos, setRepos] = useState(null);

  useEffect(() => {
    const fetchData = async () => {
      const respGlobal = await axios(`https://api.github.com/users/${username}`);
      const respRepos = await axios(`https://api.github.com/users/${username}/repos`);

      setData(respGlobal.data);
      setRepos(respRepos.data);
    };

    fetchData()

  }, []);

  if (data) {
    console.log(data, repos);
  }

  return (<h1>Hello</h1>)
}

回答1:

Multiple state updates are batched but but only if it occurs from within event handlers synchronously and not setTimeouts or async-await wrapped methods.

This behavior is similar to classes and since in your case its performing two state update cycles due to two state update calls happening

So Initially you have an initial render and then you have two state updates which is why component renders three times.

Since the two states in your case are related, you can create an object and update them together liek

function App() {
  const [resp, setGitData] = useState({ data: null, repos: null });

  useEffect(() => {
    const fetchData = async () => {
      const respGlobal = await axios(
        `https://api.github.com/users/${username}`
      );
      const respRepos = await axios(
        `https://api.github.com/users/${username}/repos`
      );

      setGitData({ data: respGlobal.data, repos: respGlobal.data });
    };

    fetchData();
  }, []);

  console.log('render');
  if (resp.data) {
    console.log("d", resp.data, resp.repos);
  }

  return <h1>Hello</h1>;
}

Working demo

来源：https://stackoverflow.com/questions/55521912/multiple-fetch-data-axios-with-react-hooks