constructor(props) {

        super(props)

        var products = [
            { name: "Motorhead glasses", price: 300, amount: 1 },
            { name: "Judaspriest glasses", price: 499, amount: 1 }
        ]

        this.state = { products: products }
        this.handleMinus = this.handleMinus.bind(this)

    }


    handleMinus(key) {
        var stateCopy = Object.assign({}, this.state);
        stateCopy.products = stateCopy.products.slice();
        stateCopy.products[key] = Object.assign({}, stateCopy.products[key]);
        stateCopy.products[key].amount += 1;
        this.setState({ [this.state.products[key].amount]: stateCopy });
        console.log(this)
    }