Кол-во с работающей кратностью

function amountInit() {
    $(".cart-products__item, .shop2-product-item, .shop2-product, .kind-item, .popup-product").each(function() {
        var $this       = $(this);
        var $amountWrap = $this.find(".shop2-product-amount");
        var $input      = $amountWrap.find('input[type="text"]');
        var $buttons    = $amountWrap.find("button");
        var $minus      = $amountWrap.find("button.amount-minus");
        var $plus       = $amountWrap.find("button.amount-plus");
        var min         = $amountWrap.find('input').data('min');
        var inputVal    = +$input.val();


        if (inputVal<=min) {
            $minus.attr("disabled", "disabled");
        }

        $buttons.on("click", function(){
            var parent = $(this).parent();
            var input  = parent.find("input");

            setTimeout(function(){
                var inputVal = +input.val();

                if (inputVal<=min) {
                    $minus.attr("disabled", "disabled");
                } else {
                    $minus.removeAttr("disabled");
                }
            }, 100);
        });

        $input.on("change", function(e) {
            var curVal = +$(this).val();

            if (curVal < min) {
                $(this).val(min);
            } else if (curVal == min) {
                $minus.attr("disabled", "disabled");
            } else if (curVal > min) {
                $minus.removeAttr("disabled");
            }
        });
    });
};