How to Use Async Await in React Render Function with Hooks

Async Await in React Render Function

Understanding the Issue

In your code, you attempt to use async await within the map function of the render function. However, this approach is not valid as async functions cannot be used directly in the render function. React's render function expects synchronous code.

Correct Approach

To use asynchronous operations within the render function, you can follow one of two approaches:

1. Data Fetching and Component Separation

Separate the data fetching logic into a separate component that handles the asynchronous operation. Then, conditionally render the UI component only when the data is available.

class ParentComponent extends React.Component {
  constructor() {
    this.state = { data: null };
  }

  componentDidMount() {
    fetch("/some/async/data")
      .then(resp => resp.json())
      .then(data => this.setState({ data }));
  }

  render() {
    return this.state.data ? <Child data={this.state.data} /> : null;
  }
}

const Child = ({ data }) => (
  <table>
    <tbody>
      {data.map((x, i) => (
        <tr key={i}>
          {x.map((y, j) => <td key={j}>{y}</td>)}
        </tr>
      ))}
    </tbody>
  </table>
);

2. Hooks with Async Effect

Use React hooks to manage asynchronous operations.

const ParentComponent = () => {
  const [data, setData] = useState(null);

  useEffect(() => {
    const getData = async () => {
      const resp = await fetch("/some/async/data");
      const json = await resp.json();
      setData(json);
    };
    getData();
  }, []);

  return data ? <Child data={data} /> : null;
};

Additional Notes

• The use of coordinates in the example can be replaced with actual longitude and latitude values.
• If your data records have unique identifiers, use those for the key attribute instead of the array index.

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