content: import React, { Component } from 'react';
  
  class Counter extends Component {
    render() {
      return (
        <div>
          <div>counter: {this.props.counterVal}</div>
          <button onClick={this.props.onIncrement} >+</button>
          <button onClick={this.props.onDecrement} >-</button>
        </div>
      );
    }
  }
  
  export default Counter;
  