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TypeError: this.state.data.map in reactjs

class Home extends Component {
  constructor(props) {
    super(props);
    this.state = {
      data: [],
      isLoaded: false,
    };
  }

  componentDidMount() {
    fetch("https://reqres.in/api/users?page=2")
      .then((res) => res.json())
      .then((json) => {
        this.setState({
          isLoaded: true,
          data: json,
 
        });
      });
  }

  render() {

var { isLoaded, data }= this.state;

if(!isLoaded){
  return<div>Is isLoaded</div>
}

else{

    return (
      <div>
        <ul>
          {() =>
            this.state.data.map((data, index) => (
              <li key={index}>Email: {data.email}</li>
            ))
          }
          ;
        </ul>
        
      </div>
    );
  }
}
}

export default Home;

Hii All , I know this question is asked many times but I cant figure it out I’am getting the error. I have checked for all the questions similar to this but haven’t found specific solution if I use another link i.e, “https://jsonplaceholder.typicode.com/users” this one the code works fine .

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Answer

The returned data from https://reqres.in/api/users?page=2 is not an array, but an object with a data property containing what you are looking for (an array). The result of the request is :

{"page":1,"per_page":6,"total":12,"total_pages":2,"data":[{"id":1,"email":"george.bluth@reqres.in","first_name":"George","last_name":"Bluth","avatar":"https://reqres.in/img/faces/1-image.jpg"},{"id":2,"email":"janet.weaver@reqres.in","first_name":"Janet","last_name":"Weaver","avatar":"https://reqres.in/img/faces/2-image.jpg"},{"id":3,"email":"emma.wong@reqres.in","first_name":"Emma","last_name":"Wong","avatar":"https://reqres.in/img/faces/3-image.jpg"},{"id":4,"email":"eve.holt@reqres.in","first_name":"Eve","last_name":"Holt","avatar":"https://reqres.in/img/faces/4-image.jpg"},{"id":5,"email":"charles.morris@reqres.in","first_name":"Charles","last_name":"Morris","avatar":"https://reqres.in/img/faces/5-image.jpg"},{"id":6,"email":"tracey.ramos@reqres.in","first_name":"Tracey","last_name":"Ramos","avatar":"https://reqres.in/img/faces/6-image.jpg"}],"support":{"url":"https://reqres.in/#support-heading","text":"To keep ReqRes free, contributions towards server costs are appreciated!"}}

So you cannot use map function, which is from the Array prototype, on the result of your request. You must access the data property first :

this.state.data.data.map((data, index) => ( // note the double data
  <li key={index}>Email: {data.email}</li>
))

You could also assign json.data to the state.data to avoid the ugly .data.data :

this.setState({
  isLoaded: true,
  data: json.data, // note the .data
});
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