old_contents: import React from 'react';
  
  import NotificationItem from './NotoficationItem';
  
  import {List, ListItem} from 'material-ui/List';
  
  
  export default class NotificationList extends React.Component {
    static propTypes = {
      data: React.PropTypes.array,
      checkNotification: React.PropTypes.func.isRequired,
    };
    render() {
      const notification = this.props.data.map((item) => {
        if (item.unread) {
          return <NotificationItem data={this.props.data} checkNotification={this.props.checkNotification} {...item} key={index}/>;
        }
      });
      console.log(notification);
      return (
        <List>
          <ListItem primaryText={'Уведомления'} disabled/>
          {notification}
        </List>
      );
    }
  }
  
new_contents: import React from 'react';
  
  import NotificationItem from './NotoficationItem';
  
  import {List, ListItem} from 'material-ui/List';
  
  
  export default class NotificationList extends React.Component {
    static propTypes = {
      data: React.PropTypes.array,
      checkNotification: React.PropTypes.func.isRequired,
    };
    render() {
      const notification = this.props.data.map((item) => {
        if (item.unread) {
          return <NotificationItem data={this.props.data} checkNotification={this.props.checkNotification} {...item} key={item.id}/>;
        }
      });
      console.log(notification);
      return (
        <List>
          <ListItem primaryText={'Уведомления'} disabled/>
          {notification}
        </List>
      );
    }
  }
  
subject: fix application