Digikam-FatClient/src/fetch.js

import React from 'react';

export class Fetch extends React.Component {
  state = {
    loading: true,
    error: false,
    done: false,
    data: [],
  };

  componentDidMount() {
    fetch(this.props.url)
      .then(res => {
        if (!res.ok) {
          throw new Error(res.status);
        }
        return res.arrayBuffer();
      })
      .then(data => this.setState({ loading: false, done: true, data }))
      .catch(error => this.setState({ loading: false, done: false, error }));
  }

  render() {
    return this.props.children(this.state);
  }
}