reduce.js

  getDashboardCommentList = (comments) => {
    return comments.reduce((previousValue, currentValue) => {
      let commentDate = moment(currentValue.node.createdAt).startOf('day');

      if (previousValue.indexOf(commentDate.toDate().valueOf()) === -1) {
        previousValue.push(commentDate.toDate().valueOf());
      }
      return previousValue;
    }, [])
      .map((date) => {
      return this.commentsForDay(new Date(date));
    });;
  }

  commentsForDay = (day) => {
    return this.props.viewer.allAnnotations.edges.filter((comment) => {
      let commentDate = new Date(comment.node.createdAt);
      return commentDate.getMonth() == day.getMonth() && commentDate.getDay() == day.getDay()
    });
  }