React.js Simple Components demo

app.js

class Button extends React.Component {  
  
  handleClick = () => {
		this.props.onClickFunction(this.props.incrementValue)
  }
  
  render() {
  	return (
    	<button onClick={this.handleClick}>
        +{this.props.incrementValue}
      </button>
    );
  }
}

const Result = (props) => {
	return <div>{props.currentCounter}</div>
}

class App extends React.Component {
	state = {counter: 0};
  
  incrementCounter = (incrementValue) => {
  	this.setState((prevState) => ({
    	counter: prevState.counter + incrementValue
    }));
  };
  
  
	render() {
  	return (
    	<div>
      <Button incrementValue={1} onClickFunction={this.incrementCounter}/>
      <Button incrementValue={5} onClickFunction={this.incrementCounter}/>
      <Button incrementValue={10} onClickFunction={this.incrementCounter}/>
      <Button incrementValue={100} onClickFunction={this.incrementCounter}/>
      <Result currentCounter={this.state.counter}/>
      </div>
    ); 
  }

}


ReactDOM.render(<App />, mountNode)