React-Firebase Render Lists

state = { posts: {} }; async componentDidMount () {     await database.on('value', (snap) => {         this.setState({ posts: snap.val() });     }); } renderPosts = () => {     if (this.state.posts !== null) {         const posts = this.state.posts;         return Object.keys(posts).map((key) => (             <div key={key}>                 <h2>{posts[key].title}</h2>                 <p>{posts[key].body}</p>             </div>         ));     } };