basic react component

gistfile1.txt

class Button extends React.Component {
  state = { counter: 0};

  handleClick = () => {
    this.setState({
      counter:this.state.counter + 1
    })
  };
  
  render() {
    return (
      <button onClick={this.handleClick}>
        {this.state.counter}
      </button>
    );
  }
}

ReactDOM.render(<Button />, mountNode);

//setState is async so this is better
handleClick = () => {
this.setState((prevState) => {
return {counter: prevState.counter + 1 };
})
};