Javascript 是否将KnockoutJS验证绑定值传递给自定义绑定？

使用KnockoutJS验证，无论字段是否通过验证，我都需要传递给自定义绑定。猜测我需要使用allBindingsAccessor参数以某种方式连接到字段级别可观察到的KnockoutJS验证，但不确定如何连接

ko.bindingHandlers.mycustombinding = {
    update: function (element, valueAccessor, allBindingsAccessor) {
        allBindings = allBindingsAccessor(),
        validationObservable = allBindings.validationObservable;    
        if (!validationObservable) {
            //do cool jQuery stuff to the element if it doesn't validate
        }
    }
};

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库向扩展的可观察对象添加了一个有效的可观察对象

var observable = ko.observable("f").extend({ number: true });
console.log(observable.isValid());