30秒学会 React 片段 – useFetch

A hook that implements fetch in a declarative manner.

• Create a custom hook that takes a url and options.
• Use the React.useState() hook to initialize the response and error state variables.
• Use the React.useEffect() hook to anychronously call fetch() and update the state varaibles accordingly.
• Return an object containting the response and error state variables.

代码实现

const useFetch = (url, options) => {
  const [response, setResponse] = React.useState(null);
  const [error, setError] = React.useState(null);

  React.useEffect(() => {
    const fetchData = async () => {
      try {
        const res = await fetch(url, options);
        const json = await res.json();
        setResponse(json);
      } catch (error) {
        setError(error);
      }
    };
    fetchData();
  }, []);

  return { response, error };
};

使用样例

const ImageFetch = props => {
  const res = useFetch('https://dog.ceo/api/breeds/image/random', {});
  if (!res.response) {
    return <div>Loading...</div>;
  }
  const imageUrl = res.response.message;
  return (
    <div>
      <img src={imageUrl} alt="avatar" width={400} height="auto" />
    </div>
  );
};

ReactDOM.render(<ImageFetch />, document.getElementById('root'));