content: import React from 'react';
  import CircularProgress from 'material-ui/CircularProgress';
  
  const Loading = ({loading = true}) => {
      if (loading) {
          return (
              <CircularProgress size={2}
                  style={{ position: 'fixed', top: '45%', left: '45%', zIndex: '999' }}/>
          );
      }
      return <div></div>
  };
  
  export default Loading;