fetch in react js code example

Example 1: 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 = `
${book.name}
`
    main.appendChild(h2)
  })
}

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

Example 2: fetch api react

// This is what I've been using, pretty straight forward
// It passes the JSON to the children as props
// Of course, you fetch what you will

import React, { Component, Fragment } from 'react';

export class FetchJsonController extends Component
{
	constructor(props) {
		super(props);
		this.state = {
			data: null,
		};
	}

	componentDidMount() {
		fetch(this.props.src)
			.then(response => response.json())
			.then(data => {
				console.log(data);
				this.setState({ data })
			});
	}

	render() {
		const _data = this.state.data;
		const children = React.Children.map(this.props.children, child => {
			return React.cloneElement(child, {
				jsonData: _data
			});
		});
		return (
			
{ children }
		)
	}
}

// This is how it's used
// SomeCompnent will receive the JSON data

  

Example 3: 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))
  }