text: import React, { Component } from 'react';
  import { connect } from 'react-redux';
  
  class BookDetail extends Component {
    render(){
      if(!this.props.book){
        return <div>Select a book.</div>;
      }
      return(
        <div>
          <h3>Details for:</h3>
          <div>Title: {this.props.book.title}</div>
          <div>Pages: {this.props.book.pages}</div>
        </div>
      );
    }
  }
  
  function mapStateToProps(state){
    return {
      book: state.activeBook
    };
  }
  
  export default connect(mapStateToProps)(BookDetail)
  