CODEWITHSUNDEEP
javascriptreactjsapi
Damien Christophe
Damien Christophe

Reputation: 115

What's the best practice to call API with react

I actually face a small problem in React when calling the API, since ComponentWillMount is deprecated.

I did this: 

class MyClass extends Component {
  constructor() {
  super();

    this.state = {
      questionsAnswers: [[{ answers: [{ text: '', id: 0 }], title: '', id: 0 }]],

    },
  };
}
componentDidMount() {
   this.getQuestions();
}

getQuestions = async () => {
   let questionsAnswers = await Subscription.getQuestionsAndAnswers();
   questionsAnswers = questionsAnswers.data;
   this.setState({ questionsAnswers });
};

So the page is rendered a first time without questionsAsnwers, when I get the questionAnswers the page is re-rendered

Is there a better solution to avoid a re-render?

Upvotes: 5

Views: 12248

Answers (3)

Ogglas
Ogglas

Reputation: 70184

Using a class with React.Component it is componentDidMount:

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      error: null,
      isLoaded: false,
      items: []
    };
  }

  componentDidMount() {
    fetch("https://api.example.com/items")
      .then(res => res.json())
      .then(
        (result) => {
          this.setState({
            isLoaded: true,
            items: result.items
          });
        },
        // Note: it's important to handle errors here
        // instead of a catch() block so that we don't swallow
        // exceptions from actual bugs in components.
        (error) => {
          this.setState({
            isLoaded: true,
            error
          });
        }
      )
  }

  render() {
    const { error, isLoaded, items } = this.state;
    if (error) {
      return <div>Error: {error.message}</div>;
    } else if (!isLoaded) {
      return <div>Loading...</div>;
    } else {
      return (
        <ul>
          {items.map(item => (
            <li key={item.id}>
              {item.name} {item.price}
            </li>
          ))}
        </ul>
      );
    }
  }
}

If you use a function component with Hooks you should do it like this:

function MyComponent() {
  const [error, setError] = useState(null);
  const [isLoaded, setIsLoaded] = useState(false);
  const [items, setItems] = useState([]);

  // Note: the empty deps array [] means
  // this useEffect will run once
  // similar to componentDidMount()
  useEffect(() => {
    fetch("https://api.example.com/items")
      .then(res => res.json())
      .then(
        (result) => {
          setIsLoaded(true);
          setItems(result);
        },
        // Note: it's important to handle errors here
        // instead of a catch() block so that we don't swallow
        // exceptions from actual bugs in components.
        (error) => {
          setIsLoaded(true);
          setError(error);
        }
      )
  }, [])

  if (error) {
    return <div>Error: {error.message}</div>;
  } else if (!isLoaded) {
    return <div>Loading...</div>;
  } else {
    return (
      <ul>
        {items.map(item => (
          <li key={item.id}>
            {item.name} {item.price}
          </li>
        ))}
      </ul>
    );
  }
}

Example response:

{
  "items": [
    { "id": 1, "name": "Apples",  "price": "$2" },
    { "id": 2, "name": "Peaches", "price": "$5" }
  ] 
}

Source:

https://reactjs.org/docs/faq-ajax.html

Upvotes: 2

EL AZIZI Youssouf
EL AZIZI Youssouf

Reputation: 325

The best way to handle API call is in the componentDidMount method react lifeCycle according to react documentation. At this moment all you can do is to add a spinner to make your component more user-friendly.
Hopefully, in the next React releases. React will introduce a new way to solve this kind of problem using the suspense approach https://medium.com/@baphemot/understanding-react-suspense-1c73b4b0b1e6

Upvotes: 3

bullgare
bullgare

Reputation: 1773

I think, it's okay to show spinner in that situation. And you should also check that ajax did not fail.

Upvotes: 0

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