ReactJS fetch() api call returning null or empty array

Question

I am trying to fetch posts from wordpress RESTapi-v2 in react component.The api supplies data in json format.But fetch response in Reactjs is returning null array of posts

below is the code

class Posts extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      error: null,
      isLoaded: false,
      posts: ''
    }
    this.fetchposts = this.fetchposts.bind(this);

  }
  fetchposts(){
    fetch("http://smashingdevs.com/wp-json/wp/v2/posts/")
      .then( 
            (result)=> {
              this.setState({
                isLoaded: true,
                posts: result,
              });
            }
         );
      console.log(this.state.posts);

  }
  render() {
    return (
      <div>
        <h2>Hello  there</h2>
        <button onClick={this.fetchposts}>
          fetch posts
        </button>
      </div>
    );
  }
}

this request requires no authentication you can check it form http://smashingdevs.com/wp-json/wp/v2/posts/.

How can i debug this? is there anyway to see what posts are being fetched in console?

your console is at wrong place

Shubham Agarwal Bhewanewala
– Shubham Agarwal Bhewanewala

2018-08-02 14:57:55 +00:00
Commented Aug 2, 2018 at 14:57 — Shubham Agarwal Bhewanewala
– Shubham Agarwal Bhewanewala, Commented Aug 2, 2018 at 14:57

João Cunha · Accepted Answer · 2018-08-02 14:57:39Z

4

a fetch call returns a response object. If you need json you must first parse it.

fetch('http://example.com/movies.json')
    .then((response) => {
        return response.json();
    })
    .then((myJson) => {
        this.setState({
          isLoaded: true,
          posts: myJson,
        });
        console.log(myJson);
    });

If you have async/await support in your app you can actually write it in a nicer way

async fetchposts() {
  let response = await fetch('http://example.com/movies.json');
  let json = await response.json();

  // do whatever
}

Another piece of advise: wrap your fetch call in a try catch and check for any errors that might occurr.

answered Aug 2, 2018 at 14:57

João Cunha

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Comments

Wolfie · Accepted Answer · 2018-08-02 14:55:14Z

The fetch api specifies that you need to transform the response into JSON before accessing the data.

Using Fetch Documentation

Example:

fetch('http://example.com/movies.json')
    .then((response) => {
        return response.json();
    })
    .then((myJson) => {
        console.log(myJson);
    });

Here we are fetching a JSON file across the network and print it to the console. The simplest use of fetch() takes one argument — the path to the resource you want to fetch — and returns a promise containing the response (a Response object).

This is just an HTTP response of course, not the actual JSON. To extract the JSON body content from the response, we use the json() method (defined on the Body mixin, which is implemented by both the Request and Response objects.)

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