handleClick = (product) => {
    product['quantity'] = 1;
    let sameItem = this.state.cartItems.findIndex(item => item.id == product.id);
    console.log(sameItem);
    if(sameItem != -1){
      if(this.state.cartItems[sameItem].quantity < 10){
        this.state.cartItems[sameItem].quantity += 1;
      }
    } else {
      let cartItems = [...this.state.cartItems, product];
      this.setState({ cartItems }, () => console.log(this.state.cartItems));
    }
    console.log(this.state.cartItems);


  }

 {/* This is all im trying to display with the cart for now, but it does not increment, but even in the console it does not increment */}
        <div>
          {cartItems.map(item => (
            <p key={item.id} >{item.quantity}</p>
          ))}
        </div>

if(this.state.cartItems[sameItem].quantity < 10){
    this.state.cartItems[sameItem].quantity += 1;
    this.setState({cartItems});
 }