public

mapview.jsx

class MapView extends React.Component  {
	constructor(props) {
		super(props)
		this.state = {
			center: 0
		}
	}
	static getDerivedStateFromProps (props, state) {
		// both props.right and props.left are simple numerical values
		let feat = props.right+ props.left
		return ( {
			center:feat,
		})
	}
	checkState = () => {
		<div>{this.state.center}</div>
	}
	render() {
		return (
			<div>
			{
				this.checkState()
			}
			</div>
			)
	}
}