before component mount react code example
Example 1: componentDidUpdate
componentDidUpdate(prevProps, prevState) {
if (prevState.pokemons !== this.state.pokemons) {
console.log('pokemons state has changed.')
}
}
Example 2: lifecycles if reactjs
class Clock extends React.Component {
constructor(props) {
super(props);
this.state = {date: new Date()};
}
componentDidMount() { }
componentWillUnmount() { }
render() {
return (
<div>
<h1>Hello, world!</h1>
<h2>It is {this.state.date.toLocaleTimeString()}.</h2>
</div>
);
}
}
Example 3: react.component
class Welcome extends React.Component {
render() {
return <h1>Hello, {this.props.name}</h1>;
}
}