在设置状态后做出承诺时，"TypeError: this.setState(...) is undefined“

handleClick = () => {
  this.setState({ key: value });
}

constructor(props) {
  super(props);
  this.handleClick = this.handleClick.bind(this);
}

handleClick() {
  this.setState({ key: value });
}

class MyComponent extends React.Component {
  handleClick = () => {
    this.setState({ key: value });
  }

  render() {
    return (
      <button onClick={this.handleClick}>Click me</button>
    );
  }
}