React: passing data from multiple child to parent -

     In 1.app.js 1 <Header onShowCart={showCartHandler}/> Go to 2.Header Component 2 <HeaderCartButton onClick={props.onShowCart}></HeaderCartButton> Go to 3.HeaderCardButton Component 3 <button className={classes.button} onClick={props.onClick}>

App.js

Header.js

HeaderCartButton.js