text: class Image extends PureComponent {
      componentDidMount() {
          this.observer = new IntersectionObserver(
              entries => {
                  entries.forEach(entry => {
                      const {
                          isIntersecting
                      } = entry;
  
                      if (isIntersecting) {
                          this.element.src = this.props.src;
                          this.observer = this.observer.disconnect();
                      }
                  });
              }, {
                  root: document.querySelector(".container")
              }
          );
          this.observer.observe(this.element);
      }
  
      render() {
          return <img ref={el => this.element = el} />;
      }
  }
  