Answers for "fetch in react js"

react fetch

componentDidMount() {
    // GET request using fetch with error handling
    fetch('https://api.npms.io/v2/invalid-url')
        .then(async response => {
            const data = await response.json();

            // check for error response
            if (!response.ok) {
                // get error message from body or default to response statusText
                const error = (data && data.message) || response.statusText;
                return Promise.reject(error);
            }

            this.setState({ totalReactPackages: data.total })
        })
        .catch(error => {
            this.setState({ errorMessage: error.toString() });
            console.error('There was an error!', error);
        });
}

how to use fetch() javascript

//Most API's will only allow you to fetch on their website.
//This means you couldn't run this code in the console on 
// google.com because:
// 		1. Google demands the fetch request be from https
// 		2. open-notify's API blocks the request outside of their website

fetch('http://api.open-notify.org/astros.json')
.then(function(response) {
  return response.json();
})
.then(function(json) {
  console.log(json)
});

// Here is another example. A method (function) that 
// grabs Game of Thrones books from an API ...

function fetchBooks() {
  return fetch('https://anapioficeandfire.com/api/books')
  .then(resp => resp.json())
  .then(json => renderBooks(json));
}

function renderBooks(json) {
  const main = document.querySelector('main')
  json.forEach(book => {
    const h2 = document.createElement('h2')
    h2.innerHTML = `<h2>${book.name}</h2>`
    main.appendChild(h2)
  })
}

document.addEventListener('DOMContentLoaded', function() {
  fetchBooks()
})

React get method

/* React get method.  */

componentWillMount(){
    fetch('/getcurrencylist',
    {
        /*
        headers: {
          'Content-Type': 'application/json',
          'Accept':'application/json'
        },
        */
        method: "get",
        dataType: 'json',
    })
    .then((res) => res.json())
    .then((data) => {
      var currencyList = [];
      for(var i=0; i< data.length; i++){
        var currency = data[i];
        currencyList.push(currency);
      }
      console.log(currencyList);
      this.setState({currencyList})
      console.log(this.state.currencyList);
    })
    .catch(err => console.log(err))
  }