2.js

import React, {Component} from 'react'
import Comment from './Comment'

class CommentList extends Component {

    render(){
        const {comments} = this.props

        const commentList = comments.map((comment) => <li key={comment.id}>
            <Comment comment={comment} />
        </li>)

        return (
            <div>
                <h2>Comments</h2>
                <ul>
                    {commentList}
                </ul>
            </div>
        )
    }
}

export default CommentList