I’ve known that I can press “enter” key to show “You pressed the enter key!” because the keycode of enter is equal to 13. So my first question is that how I can show “Raymond You pressed the enter key!” as the state.message = “”, how can I change it to what I want? And my second question is what the usage of componentWillUnmount is in this challenge, can you give me some specific details? Thanks!
**Your code so far**
class MyComponent extends React.Component {
constructor(props) {
super(props);
this.state = {
message: ''
};
this.handleEnter = this.handleEnter.bind(this);
this.handleKeyPress = this.handleKeyPress.bind(this);
}
// Change code below this line
componentDidMount() {
document.addEventListener("keydown", this.handleKeyPress)
}
componentWillUnmount() {
document.removeEventListener("keydown", this.handleKeyPress)
}
// Change code above this line
handleEnter() {
this.setState((state) => ({
message: state.message + 'You pressed the enter key! '
}));
}
handleKeyPress(event) {
if (event.keyCode === 13) {
this.handleEnter();
}
}
render() {
return (
<div>
<h1>{this.state.message}</h1>
</div>
);
}
};
**Your browser information:**
User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36
Challenge: Add Event Listeners
Link to the challenge: