var X = React.createClass({
  render: function() {
    var c = this.map(c => <Comment comment={c} key={c.id} />);
    return (
      <div className='comments'>
        {c}
      </div>
    );
  },
  foo: function() {}
});

var Comment = React.createClass({
  render: function() {
    var comment = this.props.comment;
    return (
        <li>{comment}</li>
    );
  }
  foo: function() {}
});