create object once at beginning of componet lifetime react code example
Example 1: component did update arguments
componentDidUpdate(prevProps, prevState) {
if (prevProps.data !== this.props.data) {
this.chart = c3.load({
data: this.props.data
});
}
}
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>
);
}
}