react-examples/event-handler.htm at master · arvindpdmn/react-examples · GitHub

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<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>React Event Handler</title>
</head>

<body>
    <div id="root"></div>

    <script src="https://unpkg.com/react@15/dist/react.js"></script>
    <script src="https://unpkg.com/react-dom@15/dist/react-dom.js"></script>
    <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>

    <script type="text/jsx">
class Toggle extends React.Component {
  constructor(props) {
    super(props);
    this.state = {isToggleOn: true};

    // This binding is necessary to make `this` work in the callback
    this.handleClick = this.handleClick.bind(this);
  }

  handleClick() {
    this.setState(prevState => ({
      isToggleOn: !prevState.isToggleOn
    }));
  }

  // onClick={(i) => this.handleClick(i)}
  // If this callback is passed as a prop to lower components,
  // those components might do an extra re-rendering.
  // Recommend binding in the constructor to avoid this sort of performance problem.
  // onClick={this.handleClick}
  // In constructor: this.handleClick = this.handleClick.bind(this);
  // binding makes 'this' work in the callback
  render() {
    return (
      <button onClick={this.handleClick}>
        {this.state.isToggleOn ? 'ON' : 'OFF'}
      </button>
    );
  }
}

ReactDOM.render(
  <Toggle />,
  document.getElementById('root')
);
    </script>
</body>

</html>