I'm implementing a shopping cart, that obviously will have a button to add more products. I implemented the cart context and the functionality works fine, but when I increase the number of the products to purchase it doesn't change the number displayed. What could my issue would be?

Here is my code for the context consumer

    render() {
    return (
        <CartContext.Consumer>
            {
                (cartContext =>{
                    const {addProduct} = cartContext
                        return(
                            <div>
                                <h1 key={this.props.product.itemId}> {this.state.product.name} </h1>
                                <button onClick={() => {addProduct(this.props.product.itemId)}}> Add </button>
                                <h4>{this.props.product.qty}</h4>
                                <hr/>
                            </div>
                        )
                })
            }
        </CartContext.Consumer>
    )
}