client-components-Posts.tsx

import API from 'lib/api';

export default class PostForm extends React.Component<{}, State> {
  state: State = {
    posts: null,
    isFetching: false,
    error: null,
  };

  // As soon as this component mounts, start fetching posts
  componentDidMount() {
    this.fetchPosts();
  }

  // Fetch posts from the API and store them in state
  private fetchPosts = () => {
    this.setState({ isFetching: true });

    API.fetchPosts()
      .then(posts => {
        this.setState({
          posts,
          isFetching: false,
        });
      })
      .catch(err => {
        this.setState({
          error: err.message,
          isFetching: false,
        })
      });
  };
}