import * as React from 'react' ; export interface IProps { value : number ; onIncrement : ( ) => void ; onDecrement : ( ) => void ; } export default class Counter extends React . PureComponent < IProps > { public render ( ) { const { value , onIncrement , onDecrement } = this . props ; return ( < p > Clicked : { value } times < br / > < br /> < button onClick = { onIncrement } style = { { marginRight : 20 } } > + < /button> < button onClick = { onDecrement } > - < /button> < /p>); } }