knockout.js - 意外调用方法或属性访问。仅在 IE8 中

Question

以下错误仅在 IE8 中出现...适用于 Chrome 和 Firefox 无法测试 IE9，因为我最近降级了测试目的。

Unexpected call to method or property access.

调用堆栈

相关代码标有\\Call occurs here

来自 IE 调试器的调试值...:
_frames = 对象/函数
回调 = 对象/函数
callbackTarget = 对象/函数
callbackArg = undefined

ko.dependencyDetection = (function () {
    var _frames = [];

    return {
        begin: function (callback) {
            _frames.push({ callback: callback, distinctDependencies:[] });
        },

        end: function () {
            _frames.pop();
        },

        registerDependency: function (subscribable) {
            if (!ko.isSubscribable(subscribable))
                throw new Error("Only subscribable things can act as dependencies");
            if (_frames.length > 0) {
                var topFrame = _frames[_frames.length - 1];
                if (!topFrame || ko.utils.arrayIndexOf(topFrame.distinctDependencies, subscribable) >= 0)
                    return;
                topFrame.distinctDependencies.push(subscribable);
                topFrame.callback(subscribable);
            }
        },

        ignore: function(callback, callbackTarget, callbackArgs) {
            try {
                _frames.push(null);
                return callback.apply(callbackTarget, callbackArgs || []);
            }
            //Call occurs here
            //Error occurs here since there isn't a catch and the try is failing.
            finally {
                _frames.pop();
            }
        }
    };
})();

调用自:

"notifySubscribers": function (valueToNotify, event) {
    event = event || defaultEvent;
    if (this._subscriptions[event]) {
        //Call occurs here
        ko.dependencyDetection.ignore(function() {
            ko.utils.arrayForEach(this._subscriptions[event].slice(0), function (subscription) {
                // In case a subscription was disposed during the arrayForEach cycle, check
                // for isDisposed on each subscription before invoking its callback
                if (subscription && (subscription.isDisposed !== true))
                    subscription.callback(valueToNotify);
            });
        }, this);
    }
},

调用自:

ko.observable = function (initialValue) {
    var _latestValue = initialValue;

    function observable() {
        if (arguments.length > 0) {
            // Write

            // Ignore writes if the value hasn't changed
            if ((!observable['equalityComparer']) || !observable['equalityComparer'](_latestValue, arguments[0])) {
                observable.valueWillMutate();
                _latestValue = arguments[0];
                if (DEBUG) observable._latestValue = _latestValue;
                observable.valueHasMutated();
            }
            return this; // Permits chained assignments
        }
        else {
            // Read
            ko.dependencyDetection.registerDependency(observable); // The caller only needs to be notified of changes if they did a "read" operation
            return _latestValue;
        }
    }
    if (DEBUG) observable._latestValue = _latestValue;
    ko.subscribable.call(observable);
    observable.peek = function() { return _latestValue };
    //call occurs here
    observable.valueHasMutated = function () { observable["notifySubscribers"](_latestValue); }
    observable.valueWillMutate = function () { observable["notifySubscribers"](_latestValue, "beforeChange"); }
    ko.utils.extend(observable, ko.observable['fn']);

    ko.exportProperty(observable, 'peek', observable.peek);
    ko.exportProperty(observable, "valueHasMutated", observable.valueHasMutated);
    ko.exportProperty(observable, "valueWillMutate", observable.valueWillMutate);

    return observable;
}

调用自:

ko.observable = function (initialValue) {
    var _latestValue = initialValue;

    function observable() {
        if (arguments.length > 0) {
            // Write

            // Ignore writes if the value hasn't changed
            if ((!observable['equalityComparer']) || !observable['equalityComparer'](_latestValue, arguments[0])) {
                observable.valueWillMutate();
                _latestValue = arguments[0];
                if (DEBUG) observable._latestValue = _latestValue;
                //Call occurs here
                observable.valueHasMutated();
            }
            return this; // Permits chained assignments
        }
        else {
            // Read
            ko.dependencyDetection.registerDependency(observable); // The caller only needs to be notified of changes if they did a "read" operation
            return _latestValue;
        }
    }
    if (DEBUG) observable._latestValue = _latestValue;
    ko.subscribable.call(observable);
    observable.peek = function() { return _latestValue };
    observable.valueHasMutated = function () { observable["notifySubscribers"](_latestValue); }
    observable.valueWillMutate = function () { observable["notifySubscribers"](_latestValue, "beforeChange"); }
    ko.utils.extend(observable, ko.observable['fn']);

    ko.exportProperty(observable, 'peek', observable.peek);
    ko.exportProperty(observable, "valueHasMutated", observable.valueHasMutated);
    ko.exportProperty(observable, "valueWillMutate", observable.valueWillMutate);

    return observable;
}

调用自:

self.fraudQueue(msg.d);

View 模型

function FraudQueueViewModel(runDate, analyst, fraudOid, runNumber, processed, parameter) {
    var self = this;
    self.fraudQueue = ko.observableArray();
    \\...

msg.d

无法共享真实的 msg.d 但被验证为有效的 JSON 和 JS 对象，并且是一个 array.

更新 1

错误似乎在 msg.d 的内部数组上...msg.d 包含 的 18 个内部数组对象，其中一些包含另一个内部数组。

我创建了这个 jsFiddle演示问题，但甚至无法让 IE8 打开 jsFiddle .

Answer 1

在我的具体案例中，问题是“简单”...在使用作为 IE8 运行的 IE9 调试 6 个多小时后，我将 domNode 添加到监视列表中，并且看到它未能 appendChild...我查看了 dom 元素，它是:

<td data-bind="text: viewModel.functionName(property)"></td>

我所做的只是将此绑定(bind)更改为以下内容:

<td>
    <span data-bind="text: viewModel.functionName(property)"></span>
</td>

显然 IE8 在将 function text 元素绑定(bind)到双重嵌套的 foreach 循环中时存在问题。我不确定这是否对其他人有帮助，但重要的部分是在 IE8 模式下使用 IE9 调试问题。这允许您使用 Add to watch，它允许您查看对象的属性...然后查找失败的节点，然后猜测和祈祷 .

神速...