old_contents: import React from "react";
  import moment from 'moment';
  import ReactCSSTransitionGroup from 'react-addons-css-transition-group'
  
  import NewsItem from "./NewsItem";
  import NewsCow from "./NewsCow";
  
  // const NewsItem = ({info}) => (
  //   <div className="newsItem">
  //     {info.title} <span className="subItem">{info.sitelink}</span>
  //     <div style={{position: 'absolute', bottom: 0, right: 0}}>
  //       <img src={`/dist/icons/${info.sitehost}.jpg`} />
  //     </div>
  //   </div>
  // )
  
  export default class NewsList extends React.Component {
    render () {
  
      if (this.props.loading) {
        return <div>Loading</div>
      }
  
  
      if (this.props.newsItems.length === 0) {
        return (
          <div id="emptyList">
          </div>
        );
      } else {
        var makeList = x => <li key={x.guid} className="newsItemWrapper"><NewsItem info={x}/></li>;
  
        return (
            <ReactCSSTransitionGroup component="ul" className="newsWrapper"
              transitionName="example"
              transitionAppear={true}
              transitionAppearTimeout={500}            
              transitionEnterTimeout={500}
              transitionLeaveTimeout={300}>
              { this.props.newsItems.map(makeList) }
            </ReactCSSTransitionGroup>
    		);
      }
  	}
  };
new_contents: import React from "react";
  import moment from 'moment';
  import ReactCSSTransitionGroup from 'react-addons-css-transition-group'
  
  import NewsItem from "./NewsItem";
  import NewsCow from "./NewsCow";
  
  // const NewsItem = ({info}) => (
  //   <div className="newsItem">
  //     {info.title} <span className="subItem">{info.sitelink}</span>
  //     <div style={{position: 'absolute', bottom: 0, right: 0}}>
  //       <img src={`/dist/icons/${info.sitehost}.jpg`} />
  //     </div>
  //   </div>
  // )
  
  export default class NewsList extends React.Component {
    render () {
  
      if (this.props.loading) {
        return <div>Loading</div>
      }
  
  
      if (this.props.newsItems.length === 0) {
        return (
          <div id="emptyList">
          </div>
        );
      } else {
        var makeList = x => <li key={x.itemID} className="newsItemWrapper"><NewsItem info={x}/></li>;
  
        return (
            <ReactCSSTransitionGroup component="ul" className="newsWrapper"
              transitionName="example"
              transitionAppear={true}
              transitionAppearTimeout={500}            
              transitionEnterTimeout={500}
              transitionLeaveTimeout={300}>
              { this.props.newsItems.map(makeList) }
            </ReactCSSTransitionGroup>
    		);
      }
  	}
  };
subject: Use itemID as react list key.