Clone 3.5.1 from github

vendors/knockout/src/subscribables/dependencyDetection.js

@@ -0,0 +1,76 @@
+
+ko.computedContext = ko.dependencyDetection = (function () {
+    var outerFrames = [],
+        currentFrame,
+        lastId = 0;
+
+    // Return a unique ID that can be assigned to an observable for dependency tracking.
+    // Theoretically, you could eventually overflow the number storage size, resulting
+    // in duplicate IDs. But in JavaScript, the largest exact integral value is 2^53
+    // or 9,007,199,254,740,992. If you created 1,000,000 IDs per second, it would
+    // take over 285 years to reach that number.
+    // Reference http://blog.vjeux.com/2010/javascript/javascript-max_int-number-limits.html
+    function getId() {
+        return ++lastId;
+    }
+
+    function begin(options) {
+        outerFrames.push(currentFrame);
+        currentFrame = options;
+    }
+
+    function end() {
+        currentFrame = outerFrames.pop();
+    }
+
+    return {
+        begin: begin,
+
+        end: end,
+
+        registerDependency: function (subscribable) {
+            if (currentFrame) {
+                if (!ko.isSubscribable(subscribable))
+                    throw new Error("Only subscribable things can act as dependencies");
+                currentFrame.callback.call(currentFrame.callbackTarget, subscribable, subscribable._id || (subscribable._id = getId()));
+            }
+        },
+
+        ignore: function (callback, callbackTarget, callbackArgs) {
+            try {
+                begin();
+                return callback.apply(callbackTarget, callbackArgs || []);
+            } finally {
+                end();
+            }
+        },
+
+        getDependenciesCount: function () {
+            if (currentFrame)
+                return currentFrame.computed.getDependenciesCount();
+        },
+
+        getDependencies: function () {
+            if (currentFrame)
+                return currentFrame.computed.getDependencies();
+        },
+
+        isInitial: function() {
+            if (currentFrame)
+                return currentFrame.isInitial;
+        },
+
+        computed: function() {
+            if (currentFrame)
+                return currentFrame.computed;
+        }
+    };
+})();
+
+ko.exportSymbol('computedContext', ko.computedContext);
+ko.exportSymbol('computedContext.getDependenciesCount', ko.computedContext.getDependenciesCount);
+ko.exportSymbol('computedContext.getDependencies', ko.computedContext.getDependencies);
+ko.exportSymbol('computedContext.isInitial', ko.computedContext.isInitial);
+ko.exportSymbol('computedContext.registerDependency', ko.computedContext.registerDependency);
+
+ko.exportSymbol('ignoreDependencies', ko.ignoreDependencies = ko.dependencyDetection.ignore);

vendors/knockout/src/subscribables/dependentObservable.js

@@ -0,0 +1,541 @@
+var computedState = ko.utils.createSymbolOrString('_state');
+
+ko.computed = ko.dependentObservable = function (evaluatorFunctionOrOptions, evaluatorFunctionTarget, options) {
+    if (typeof evaluatorFunctionOrOptions === "object") {
+        // Single-parameter syntax - everything is on this "options" param
+        options = evaluatorFunctionOrOptions;
+    } else {
+        // Multi-parameter syntax - construct the options according to the params passed
+        options = options || {};
+        if (evaluatorFunctionOrOptions) {
+            options["read"] = evaluatorFunctionOrOptions;
+        }
+    }
+    if (typeof options["read"] != "function")
+        throw Error("Pass a function that returns the value of the ko.computed");
+
+    var writeFunction = options["write"];
+    var state = {
+        latestValue: undefined,
+        isStale: true,
+        isDirty: true,
+        isBeingEvaluated: false,
+        suppressDisposalUntilDisposeWhenReturnsFalse: false,
+        isDisposed: false,
+        pure: false,
+        isSleeping: false,
+        readFunction: options["read"],
+        evaluatorFunctionTarget: evaluatorFunctionTarget || options["owner"],
+        disposeWhenNodeIsRemoved: options["disposeWhenNodeIsRemoved"] || options.disposeWhenNodeIsRemoved || null,
+        disposeWhen: options["disposeWhen"] || options.disposeWhen,
+        domNodeDisposalCallback: null,
+        dependencyTracking: {},
+        dependenciesCount: 0,
+        evaluationTimeoutInstance: null
+    };
+
+    function computedObservable() {
+        if (arguments.length > 0) {
+            if (typeof writeFunction === "function") {
+                // Writing a value
+                writeFunction.apply(state.evaluatorFunctionTarget, arguments);
+            } else {
+                throw new Error("Cannot write a value to a ko.computed unless you specify a 'write' option. If you wish to read the current value, don't pass any parameters.");
+            }
+            return this; // Permits chained assignments
+        } else {
+            // Reading the value
+            if (!state.isDisposed) {
+                ko.dependencyDetection.registerDependency(computedObservable);
+            }
+            if (state.isDirty || (state.isSleeping && computedObservable.haveDependenciesChanged())) {
+                computedObservable.evaluateImmediate();
+            }
+            return state.latestValue;
+        }
+    }
+
+    computedObservable[computedState] = state;
+    computedObservable.hasWriteFunction = typeof writeFunction === "function";
+
+    // Inherit from 'subscribable'
+    if (!ko.utils.canSetPrototype) {
+        // 'subscribable' won't be on the prototype chain unless we put it there directly
+        ko.utils.extend(computedObservable, ko.subscribable['fn']);
+    }
+    ko.subscribable['fn'].init(computedObservable);
+
+    // Inherit from 'computed'
+    ko.utils.setPrototypeOfOrExtend(computedObservable, computedFn);
+
+    if (options['pure']) {
+        state.pure = true;
+        state.isSleeping = true;     // Starts off sleeping; will awake on the first subscription
+        ko.utils.extend(computedObservable, pureComputedOverrides);
+    } else if (options['deferEvaluation']) {
+        ko.utils.extend(computedObservable, deferEvaluationOverrides);
+    }
+
+    if (ko.options['deferUpdates']) {
+        ko.extenders['deferred'](computedObservable, true);
+    }
+
+    if (DEBUG) {
+        // #1731 - Aid debugging by exposing the computed's options
+        computedObservable["_options"] = options;
+    }
+
+    if (state.disposeWhenNodeIsRemoved) {
+        // Since this computed is associated with a DOM node, and we don't want to dispose the computed
+        // until the DOM node is *removed* from the document (as opposed to never having been in the document),
+        // we'll prevent disposal until "disposeWhen" first returns false.
+        state.suppressDisposalUntilDisposeWhenReturnsFalse = true;
+
+        // disposeWhenNodeIsRemoved: true can be used to opt into the "only dispose after first false result"
+        // behaviour even if there's no specific node to watch. In that case, clear the option so we don't try
+        // to watch for a non-node's disposal. This technique is intended for KO's internal use only and shouldn't
+        // be documented or used by application code, as it's likely to change in a future version of KO.
+        if (!state.disposeWhenNodeIsRemoved.nodeType) {
+            state.disposeWhenNodeIsRemoved = null;
+        }
+    }
+
+    // Evaluate, unless sleeping or deferEvaluation is true
+    if (!state.isSleeping && !options['deferEvaluation']) {
+        computedObservable.evaluateImmediate();
+    }
+
+    // Attach a DOM node disposal callback so that the computed will be proactively disposed as soon as the node is
+    // removed using ko.removeNode. But skip if isActive is false (there will never be any dependencies to dispose).
+    if (state.disposeWhenNodeIsRemoved && computedObservable.isActive()) {
+        ko.utils.domNodeDisposal.addDisposeCallback(state.disposeWhenNodeIsRemoved, state.domNodeDisposalCallback = function () {
+            computedObservable.dispose();
+        });
+    }
+
+    return computedObservable;
+};
+
+// Utility function that disposes a given dependencyTracking entry
+function computedDisposeDependencyCallback(id, entryToDispose) {
+    if (entryToDispose !== null && entryToDispose.dispose) {
+        entryToDispose.dispose();
+    }
+}
+
+// This function gets called each time a dependency is detected while evaluating a computed.
+// It's factored out as a shared function to avoid creating unnecessary function instances during evaluation.
+function computedBeginDependencyDetectionCallback(subscribable, id) {
+    var computedObservable = this.computedObservable,
+        state = computedObservable[computedState];
+    if (!state.isDisposed) {
+        if (this.disposalCount && this.disposalCandidates[id]) {
+            // Don't want to dispose this subscription, as it's still being used
+            computedObservable.addDependencyTracking(id, subscribable, this.disposalCandidates[id]);
+            this.disposalCandidates[id] = null; // No need to actually delete the property - disposalCandidates is a transient object anyway
+            --this.disposalCount;
+        } else if (!state.dependencyTracking[id]) {
+            // Brand new subscription - add it
+            computedObservable.addDependencyTracking(id, subscribable, state.isSleeping ? { _target: subscribable } : computedObservable.subscribeToDependency(subscribable));
+        }
+        // If the observable we've accessed has a pending notification, ensure we get notified of the actual final value (bypass equality checks)
+        if (subscribable._notificationIsPending) {
+            subscribable._notifyNextChangeIfValueIsDifferent();
+        }
+    }
+}
+
+var computedFn = {
+    "equalityComparer": valuesArePrimitiveAndEqual,
+    getDependenciesCount: function () {
+        return this[computedState].dependenciesCount;
+    },
+    getDependencies: function () {
+        var dependencyTracking = this[computedState].dependencyTracking, dependentObservables = [];
+
+        ko.utils.objectForEach(dependencyTracking, function (id, dependency) {
+            dependentObservables[dependency._order] = dependency._target;
+        });
+
+        return dependentObservables;
+    },
+    hasAncestorDependency: function (obs) {
+        if (!this[computedState].dependenciesCount) {
+            return false;
+        }
+        var dependencies = this.getDependencies();
+        if (ko.utils.arrayIndexOf(dependencies, obs) !== -1) {
+            return true;
+        }
+        return !!ko.utils.arrayFirst(dependencies, function (dep) {
+            return dep.hasAncestorDependency && dep.hasAncestorDependency(obs);
+        });
+    },
+    addDependencyTracking: function (id, target, trackingObj) {
+        if (this[computedState].pure && target === this) {
+            throw Error("A 'pure' computed must not be called recursively");
+        }
+
+        this[computedState].dependencyTracking[id] = trackingObj;
+        trackingObj._order = this[computedState].dependenciesCount++;
+        trackingObj._version = target.getVersion();
+    },
+    haveDependenciesChanged: function () {
+        var id, dependency, dependencyTracking = this[computedState].dependencyTracking;
+        for (id in dependencyTracking) {
+            if (Object.prototype.hasOwnProperty.call(dependencyTracking, id)) {
+                dependency = dependencyTracking[id];
+                if ((this._evalDelayed && dependency._target._notificationIsPending) || dependency._target.hasChanged(dependency._version)) {
+                    return true;
+                }
+            }
+        }
+    },
+    markDirty: function () {
+        // Process "dirty" events if we can handle delayed notifications
+        if (this._evalDelayed && !this[computedState].isBeingEvaluated) {
+            this._evalDelayed(false /*isChange*/);
+        }
+    },
+    isActive: function () {
+        var state = this[computedState];
+        return state.isDirty || state.dependenciesCount > 0;
+    },
+    respondToChange: function () {
+        // Ignore "change" events if we've already scheduled a delayed notification
+        if (!this._notificationIsPending) {
+            this.evaluatePossiblyAsync();
+        } else if (this[computedState].isDirty) {
+            this[computedState].isStale = true;
+        }
+    },
+    subscribeToDependency: function (target) {
+        if (target._deferUpdates) {
+            var dirtySub = target.subscribe(this.markDirty, this, 'dirty'),
+                changeSub = target.subscribe(this.respondToChange, this);
+            return {
+                _target: target,
+                dispose: function () {
+                    dirtySub.dispose();
+                    changeSub.dispose();
+                }
+            };
+        } else {
+            return target.subscribe(this.evaluatePossiblyAsync, this);
+        }
+    },
+    evaluatePossiblyAsync: function () {
+        var computedObservable = this,
+            throttleEvaluationTimeout = computedObservable['throttleEvaluation'];
+        if (throttleEvaluationTimeout && throttleEvaluationTimeout >= 0) {
+            clearTimeout(this[computedState].evaluationTimeoutInstance);
+            this[computedState].evaluationTimeoutInstance = ko.utils.setTimeout(function () {
+                computedObservable.evaluateImmediate(true /*notifyChange*/);
+            }, throttleEvaluationTimeout);
+        } else if (computedObservable._evalDelayed) {
+            computedObservable._evalDelayed(true /*isChange*/);
+        } else {
+            computedObservable.evaluateImmediate(true /*notifyChange*/);
+        }
+    },
+    evaluateImmediate: function (notifyChange) {
+        var computedObservable = this,
+            state = computedObservable[computedState],
+            disposeWhen = state.disposeWhen,
+            changed = false;
+
+        if (state.isBeingEvaluated) {
+            // If the evaluation of a ko.computed causes side effects, it's possible that it will trigger its own re-evaluation.
+            // This is not desirable (it's hard for a developer to realise a chain of dependencies might cause this, and they almost
+            // certainly didn't intend infinite re-evaluations). So, for predictability, we simply prevent ko.computeds from causing
+            // their own re-evaluation. Further discussion at https://github.com/SteveSanderson/knockout/pull/387
+            return;
+        }
+
+        // Do not evaluate (and possibly capture new dependencies) if disposed
+        if (state.isDisposed) {
+            return;
+        }
+
+        if (state.disposeWhenNodeIsRemoved && !ko.utils.domNodeIsAttachedToDocument(state.disposeWhenNodeIsRemoved) || disposeWhen && disposeWhen()) {
+            // See comment above about suppressDisposalUntilDisposeWhenReturnsFalse
+            if (!state.suppressDisposalUntilDisposeWhenReturnsFalse) {
+                computedObservable.dispose();
+                return;
+            }
+        } else {
+            // It just did return false, so we can stop suppressing now
+            state.suppressDisposalUntilDisposeWhenReturnsFalse = false;
+        }
+
+        state.isBeingEvaluated = true;
+        try {
+            changed = this.evaluateImmediate_CallReadWithDependencyDetection(notifyChange);
+        } finally {
+            state.isBeingEvaluated = false;
+        }
+
+        return changed;
+    },
+    evaluateImmediate_CallReadWithDependencyDetection: function (notifyChange) {
+        // This function is really just part of the evaluateImmediate logic. You would never call it from anywhere else.
+        // Factoring it out into a separate function means it can be independent of the try/catch block in evaluateImmediate,
+        // which contributes to saving about 40% off the CPU overhead of computed evaluation (on V8 at least).
+
+        var computedObservable = this,
+            state = computedObservable[computedState],
+            changed = false;
+
+        // Initially, we assume that none of the subscriptions are still being used (i.e., all are candidates for disposal).
+        // Then, during evaluation, we cross off any that are in fact still being used.
+        var isInitial = state.pure ? undefined : !state.dependenciesCount,   // If we're evaluating when there are no previous dependencies, it must be the first time
+            dependencyDetectionContext = {
+                computedObservable: computedObservable,
+                disposalCandidates: state.dependencyTracking,
+                disposalCount: state.dependenciesCount
+            };
+
+        ko.dependencyDetection.begin({
+            callbackTarget: dependencyDetectionContext,
+            callback: computedBeginDependencyDetectionCallback,
+            computed: computedObservable,
+            isInitial: isInitial
+        });
+
+        state.dependencyTracking = {};
+        state.dependenciesCount = 0;
+
+        var newValue = this.evaluateImmediate_CallReadThenEndDependencyDetection(state, dependencyDetectionContext);
+
+        if (!state.dependenciesCount) {
+            computedObservable.dispose();
+            changed = true; // When evaluation causes a disposal, make sure all dependent computeds get notified so they'll see the new state
+        } else {
+            changed = computedObservable.isDifferent(state.latestValue, newValue);
+        }
+
+        if (changed) {
+            if (!state.isSleeping) {
+                computedObservable["notifySubscribers"](state.latestValue, "beforeChange");
+            } else {
+                computedObservable.updateVersion();
+            }
+
+            state.latestValue = newValue;
+            if (DEBUG) computedObservable._latestValue = newValue;
+
+            computedObservable["notifySubscribers"](state.latestValue, "spectate");
+
+            if (!state.isSleeping && notifyChange) {
+                computedObservable["notifySubscribers"](state.latestValue);
+            }
+            if (computedObservable._recordUpdate) {
+                computedObservable._recordUpdate();
+            }
+        }
+
+        if (isInitial) {
+            computedObservable["notifySubscribers"](state.latestValue, "awake");
+        }
+
+        return changed;
+    },
+    evaluateImmediate_CallReadThenEndDependencyDetection: function (state, dependencyDetectionContext) {
+        // This function is really part of the evaluateImmediate_CallReadWithDependencyDetection logic.
+        // You'd never call it from anywhere else. Factoring it out means that evaluateImmediate_CallReadWithDependencyDetection
+        // can be independent of try/finally blocks, which contributes to saving about 40% off the CPU
+        // overhead of computed evaluation (on V8 at least).
+
+        try {
+            var readFunction = state.readFunction;
+            return state.evaluatorFunctionTarget ? readFunction.call(state.evaluatorFunctionTarget) : readFunction();
+        } finally {
+            ko.dependencyDetection.end();
+
+            // For each subscription no longer being used, remove it from the active subscriptions list and dispose it
+            if (dependencyDetectionContext.disposalCount && !state.isSleeping) {
+                ko.utils.objectForEach(dependencyDetectionContext.disposalCandidates, computedDisposeDependencyCallback);
+            }
+
+            state.isStale = state.isDirty = false;
+        }
+    },
+    peek: function (evaluate) {
+        // By default, peek won't re-evaluate, except while the computed is sleeping or to get the initial value when "deferEvaluation" is set.
+        // Pass in true to evaluate if needed.
+        var state = this[computedState];
+        if ((state.isDirty && (evaluate || !state.dependenciesCount)) || (state.isSleeping && this.haveDependenciesChanged())) {
+            this.evaluateImmediate();
+        }
+        return state.latestValue;
+    },
+    limit: function (limitFunction) {
+        // Override the limit function with one that delays evaluation as well
+        ko.subscribable['fn'].limit.call(this, limitFunction);
+        this._evalIfChanged = function () {
+            if (!this[computedState].isSleeping) {
+                if (this[computedState].isStale) {
+                    this.evaluateImmediate();
+                } else {
+                    this[computedState].isDirty = false;
+                }
+            }
+            return this[computedState].latestValue;
+        };
+        this._evalDelayed = function (isChange) {
+            this._limitBeforeChange(this[computedState].latestValue);
+
+            // Mark as dirty
+            this[computedState].isDirty = true;
+            if (isChange) {
+                this[computedState].isStale = true;
+            }
+
+            // Pass the observable to the "limit" code, which will evaluate it when
+            // it's time to do the notification.
+            this._limitChange(this, !isChange /* isDirty */);
+        };
+    },
+    dispose: function () {
+        var state = this[computedState];
+        if (!state.isSleeping && state.dependencyTracking) {
+            ko.utils.objectForEach(state.dependencyTracking, function (id, dependency) {
+                if (dependency.dispose)
+                    dependency.dispose();
+            });
+        }
+        if (state.disposeWhenNodeIsRemoved && state.domNodeDisposalCallback) {
+            ko.utils.domNodeDisposal.removeDisposeCallback(state.disposeWhenNodeIsRemoved, state.domNodeDisposalCallback);
+        }
+        state.dependencyTracking = undefined;
+        state.dependenciesCount = 0;
+        state.isDisposed = true;
+        state.isStale = false;
+        state.isDirty = false;
+        state.isSleeping = false;
+        state.disposeWhenNodeIsRemoved = undefined;
+        state.disposeWhen = undefined;
+        state.readFunction = undefined;
+        if (!this.hasWriteFunction) {
+            state.evaluatorFunctionTarget = undefined;
+        }
+    }
+};
+
+var pureComputedOverrides = {
+    beforeSubscriptionAdd: function (event) {
+        // If asleep, wake up the computed by subscribing to any dependencies.
+        var computedObservable = this,
+            state = computedObservable[computedState];
+        if (!state.isDisposed && state.isSleeping && event == 'change') {
+            state.isSleeping = false;
+            if (state.isStale || computedObservable.haveDependenciesChanged()) {
+                state.dependencyTracking = null;
+                state.dependenciesCount = 0;
+                if (computedObservable.evaluateImmediate()) {
+                    computedObservable.updateVersion();
+                }
+            } else {
+                // First put the dependencies in order
+                var dependenciesOrder = [];
+                ko.utils.objectForEach(state.dependencyTracking, function (id, dependency) {
+                    dependenciesOrder[dependency._order] = id;
+                });
+                // Next, subscribe to each one
+                ko.utils.arrayForEach(dependenciesOrder, function (id, order) {
+                    var dependency = state.dependencyTracking[id],
+                        subscription = computedObservable.subscribeToDependency(dependency._target);
+                    subscription._order = order;
+                    subscription._version = dependency._version;
+                    state.dependencyTracking[id] = subscription;
+                });
+                // Waking dependencies may have triggered effects
+                if (computedObservable.haveDependenciesChanged()) {
+                    if (computedObservable.evaluateImmediate()) {
+                        computedObservable.updateVersion();
+                    }
+                }
+            }
+
+            if (!state.isDisposed) {     // test since evaluating could trigger disposal
+                computedObservable["notifySubscribers"](state.latestValue, "awake");
+            }
+        }
+    },
+    afterSubscriptionRemove: function (event) {
+        var state = this[computedState];
+        if (!state.isDisposed && event == 'change' && !this.hasSubscriptionsForEvent('change')) {
+            ko.utils.objectForEach(state.dependencyTracking, function (id, dependency) {
+                if (dependency.dispose) {
+                    state.dependencyTracking[id] = {
+                        _target: dependency._target,
+                        _order: dependency._order,
+                        _version: dependency._version
+                    };
+                    dependency.dispose();
+                }
+            });
+            state.isSleeping = true;
+            this["notifySubscribers"](undefined, "asleep");
+        }
+    },
+    getVersion: function () {
+        // Because a pure computed is not automatically updated while it is sleeping, we can't
+        // simply return the version number. Instead, we check if any of the dependencies have
+        // changed and conditionally re-evaluate the computed observable.
+        var state = this[computedState];
+        if (state.isSleeping && (state.isStale || this.haveDependenciesChanged())) {
+            this.evaluateImmediate();
+        }
+        return ko.subscribable['fn'].getVersion.call(this);
+    }
+};
+
+var deferEvaluationOverrides = {
+    beforeSubscriptionAdd: function (event) {
+        // This will force a computed with deferEvaluation to evaluate when the first subscription is registered.
+        if (event == 'change' || event == 'beforeChange') {
+            this.peek();
+        }
+    }
+};
+
+// Note that for browsers that don't support proto assignment, the
+// inheritance chain is created manually in the ko.computed constructor
+if (ko.utils.canSetPrototype) {
+    ko.utils.setPrototypeOf(computedFn, ko.subscribable['fn']);
+}
+
+// Set the proto values for ko.computed
+var protoProp = ko.observable.protoProperty; // == "__ko_proto__"
+computedFn[protoProp] = ko.computed;
+
+ko.isComputed = function (instance) {
+    return (typeof instance == 'function' && instance[protoProp] === computedFn[protoProp]);
+};
+
+ko.isPureComputed = function (instance) {
+    return ko.isComputed(instance) && instance[computedState] && instance[computedState].pure;
+};
+
+ko.exportSymbol('computed', ko.computed);
+ko.exportSymbol('dependentObservable', ko.computed);    // export ko.dependentObservable for backwards compatibility (1.x)
+ko.exportSymbol('isComputed', ko.isComputed);
+ko.exportSymbol('isPureComputed', ko.isPureComputed);
+ko.exportSymbol('computed.fn', computedFn);
+ko.exportProperty(computedFn, 'peek', computedFn.peek);
+ko.exportProperty(computedFn, 'dispose', computedFn.dispose);
+ko.exportProperty(computedFn, 'isActive', computedFn.isActive);
+ko.exportProperty(computedFn, 'getDependenciesCount', computedFn.getDependenciesCount);
+ko.exportProperty(computedFn, 'getDependencies', computedFn.getDependencies);
+
+ko.pureComputed = function (evaluatorFunctionOrOptions, evaluatorFunctionTarget) {
+    if (typeof evaluatorFunctionOrOptions === 'function') {
+        return ko.computed(evaluatorFunctionOrOptions, evaluatorFunctionTarget, {'pure':true});
+    } else {
+        evaluatorFunctionOrOptions = ko.utils.extend({}, evaluatorFunctionOrOptions);   // make a copy of the parameter object
+        evaluatorFunctionOrOptions['pure'] = true;
+        return ko.computed(evaluatorFunctionOrOptions, evaluatorFunctionTarget);
+    }
+}
+ko.exportSymbol('pureComputed', ko.pureComputed);

vendors/knockout/src/subscribables/extenders.js

@@ -0,0 +1,115 @@
+ko.extenders = {
+    'throttle': function(target, timeout) {
+        // Throttling means two things:
+
+        // (1) For dependent observables, we throttle *evaluations* so that, no matter how fast its dependencies
+        //     notify updates, the target doesn't re-evaluate (and hence doesn't notify) faster than a certain rate
+        target['throttleEvaluation'] = timeout;
+
+        // (2) For writable targets (observables, or writable dependent observables), we throttle *writes*
+        //     so the target cannot change value synchronously or faster than a certain rate
+        var writeTimeoutInstance = null;
+        return ko.dependentObservable({
+            'read': target,
+            'write': function(value) {
+                clearTimeout(writeTimeoutInstance);
+                writeTimeoutInstance = ko.utils.setTimeout(function() {
+                    target(value);
+                }, timeout);
+            }
+        });
+    },
+
+    'rateLimit': function(target, options) {
+        var timeout, method, limitFunction;
+
+        if (typeof options == 'number') {
+            timeout = options;
+        } else {
+            timeout = options['timeout'];
+            method = options['method'];
+        }
+
+        // rateLimit supersedes deferred updates
+        target._deferUpdates = false;
+
+        limitFunction = typeof method == 'function' ? method : method == 'notifyWhenChangesStop' ?  debounce : throttle;
+        target.limit(function(callback) {
+            return limitFunction(callback, timeout, options);
+        });
+    },
+
+    'deferred': function(target, options) {
+        if (options !== true) {
+            throw new Error('The \'deferred\' extender only accepts the value \'true\', because it is not supported to turn deferral off once enabled.')
+        }
+
+        if (!target._deferUpdates) {
+            target._deferUpdates = true;
+            target.limit(function (callback) {
+                var handle,
+                    ignoreUpdates = false;
+                return function () {
+                    if (!ignoreUpdates) {
+                        ko.tasks.cancel(handle);
+                        handle = ko.tasks.schedule(callback);
+
+                        try {
+                            ignoreUpdates = true;
+                            target['notifySubscribers'](undefined, 'dirty');
+                        } finally {
+                            ignoreUpdates = false;
+                        }
+                    }
+                };
+            });
+        }
+    },
+
+    'notify': function(target, notifyWhen) {
+        target["equalityComparer"] = notifyWhen == "always" ?
+            null :  // null equalityComparer means to always notify
+            valuesArePrimitiveAndEqual;
+    }
+};
+
+var primitiveTypes = { 'undefined':1, 'boolean':1, 'number':1, 'string':1 };
+function valuesArePrimitiveAndEqual(a, b) {
+    var oldValueIsPrimitive = (a === null) || (typeof(a) in primitiveTypes);
+    return oldValueIsPrimitive ? (a === b) : false;
+}
+
+function throttle(callback, timeout) {
+    var timeoutInstance;
+    return function () {
+        if (!timeoutInstance) {
+            timeoutInstance = ko.utils.setTimeout(function () {
+                timeoutInstance = undefined;
+                callback();
+            }, timeout);
+        }
+    };
+}
+
+function debounce(callback, timeout) {
+    var timeoutInstance;
+    return function () {
+        clearTimeout(timeoutInstance);
+        timeoutInstance = ko.utils.setTimeout(callback, timeout);
+    };
+}
+
+function applyExtenders(requestedExtenders) {
+    var target = this;
+    if (requestedExtenders) {
+        ko.utils.objectForEach(requestedExtenders, function(key, value) {
+            var extenderHandler = ko.extenders[key];
+            if (typeof extenderHandler == 'function') {
+                target = extenderHandler(target, value) || target;
+            }
+        });
+    }
+    return target;
+}
+
+ko.exportSymbol('extenders', ko.extenders);

vendors/knockout/src/subscribables/mappingHelpers.js

@@ -0,0 +1,96 @@
+
+(function() {
+    var maxNestedObservableDepth = 10; // Escape the (unlikely) pathological case where an observable's current value is itself (or similar reference cycle)
+
+    ko.toJS = function(rootObject) {
+        if (arguments.length == 0)
+            throw new Error("When calling ko.toJS, pass the object you want to convert.");
+
+        // We just unwrap everything at every level in the object graph
+        return mapJsObjectGraph(rootObject, function(valueToMap) {
+            // Loop because an observable's value might in turn be another observable wrapper
+            for (var i = 0; ko.isObservable(valueToMap) && (i < maxNestedObservableDepth); i++)
+                valueToMap = valueToMap();
+            return valueToMap;
+        });
+    };
+
+    ko.toJSON = function(rootObject, replacer, space) {     // replacer and space are optional
+        var plainJavaScriptObject = ko.toJS(rootObject);
+        return ko.utils.stringifyJson(plainJavaScriptObject, replacer, space);
+    };
+
+    function mapJsObjectGraph(rootObject, mapInputCallback, visitedObjects) {
+        visitedObjects = visitedObjects || new objectLookup();
+
+        rootObject = mapInputCallback(rootObject);
+        var canHaveProperties = (typeof rootObject == "object") && (rootObject !== null) && (rootObject !== undefined) && (!(rootObject instanceof RegExp)) && (!(rootObject instanceof Date)) && (!(rootObject instanceof String)) && (!(rootObject instanceof Number)) && (!(rootObject instanceof Boolean));
+        if (!canHaveProperties)
+            return rootObject;
+
+        var outputProperties = rootObject instanceof Array ? [] : {};
+        visitedObjects.save(rootObject, outputProperties);
+
+        visitPropertiesOrArrayEntries(rootObject, function(indexer) {
+            var propertyValue = mapInputCallback(rootObject[indexer]);
+
+            switch (typeof propertyValue) {
+                case "boolean":
+                case "number":
+                case "string":
+                case "function":
+                    outputProperties[indexer] = propertyValue;
+                    break;
+                case "object":
+                case "undefined":
+                    var previouslyMappedValue = visitedObjects.get(propertyValue);
+                    outputProperties[indexer] = (previouslyMappedValue !== undefined)
+                        ? previouslyMappedValue
+                        : mapJsObjectGraph(propertyValue, mapInputCallback, visitedObjects);
+                    break;
+            }
+        });
+
+        return outputProperties;
+    }
+
+    function visitPropertiesOrArrayEntries(rootObject, visitorCallback) {
+        if (rootObject instanceof Array) {
+            for (var i = 0; i < rootObject.length; i++)
+                visitorCallback(i);
+
+            // For arrays, also respect toJSON property for custom mappings (fixes #278)
+            if (typeof rootObject['toJSON'] == 'function')
+                visitorCallback('toJSON');
+        } else {
+            for (var propertyName in rootObject) {
+                visitorCallback(propertyName);
+            }
+        }
+    };
+
+    function objectLookup() {
+        this.keys = [];
+        this.values = [];
+    };
+
+    objectLookup.prototype = {
+        constructor: objectLookup,
+        save: function(key, value) {
+            var existingIndex = ko.utils.arrayIndexOf(this.keys, key);
+            if (existingIndex >= 0)
+                this.values[existingIndex] = value;
+            else {
+                this.keys.push(key);
+                this.values.push(value);
+            }
+        },
+        get: function(key) {
+            var existingIndex = ko.utils.arrayIndexOf(this.keys, key);
+            return (existingIndex >= 0) ? this.values[existingIndex] : undefined;
+        }
+    };
+})();
+
+ko.exportSymbol('toJS', ko.toJS);
+ko.exportSymbol('toJSON', ko.toJSON);

vendors/knockout/src/subscribables/observable.js

@@ -0,0 +1,83 @@
+var observableLatestValue = ko.utils.createSymbolOrString('_latestValue');
+
+ko.observable = function (initialValue) {
+    function observable() {
+        if (arguments.length > 0) {
+            // Write
+
+            // Ignore writes if the value hasn't changed
+            if (observable.isDifferent(observable[observableLatestValue], arguments[0])) {
+                observable.valueWillMutate();
+                observable[observableLatestValue] = arguments[0];
+                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 observable[observableLatestValue];
+        }
+    }
+
+    observable[observableLatestValue] = initialValue;
+
+    // Inherit from 'subscribable'
+    if (!ko.utils.canSetPrototype) {
+        // 'subscribable' won't be on the prototype chain unless we put it there directly
+        ko.utils.extend(observable, ko.subscribable['fn']);
+    }
+    ko.subscribable['fn'].init(observable);
+
+    // Inherit from 'observable'
+    ko.utils.setPrototypeOfOrExtend(observable, observableFn);
+
+    if (ko.options['deferUpdates']) {
+        ko.extenders['deferred'](observable, true);
+    }
+
+    return observable;
+}
+
+// Define prototype for observables
+var observableFn = {
+    'equalityComparer': valuesArePrimitiveAndEqual,
+    peek: function() { return this[observableLatestValue]; },
+    valueHasMutated: function () {
+        this['notifySubscribers'](this[observableLatestValue], 'spectate');
+        this['notifySubscribers'](this[observableLatestValue]);
+    },
+    valueWillMutate: function () { this['notifySubscribers'](this[observableLatestValue], 'beforeChange'); }
+};
+
+// Note that for browsers that don't support proto assignment, the
+// inheritance chain is created manually in the ko.observable constructor
+if (ko.utils.canSetPrototype) {
+    ko.utils.setPrototypeOf(observableFn, ko.subscribable['fn']);
+}
+
+var protoProperty = ko.observable.protoProperty = '__ko_proto__';
+observableFn[protoProperty] = ko.observable;
+
+ko.isObservable = function (instance) {
+    var proto = typeof instance == 'function' && instance[protoProperty];
+    if (proto && proto !== observableFn[protoProperty] && proto !== ko.computed['fn'][protoProperty]) {
+        throw Error("Invalid object that looks like an observable; possibly from another Knockout instance");
+    }
+    return !!proto;
+};
+
+ko.isWriteableObservable = function (instance) {
+    return (typeof instance == 'function' && (
+        (instance[protoProperty] === observableFn[protoProperty]) ||  // Observable
+        (instance[protoProperty] === ko.computed['fn'][protoProperty] && instance.hasWriteFunction)));   // Writable computed observable
+};
+
+ko.exportSymbol('observable', ko.observable);
+ko.exportSymbol('isObservable', ko.isObservable);
+ko.exportSymbol('isWriteableObservable', ko.isWriteableObservable);
+ko.exportSymbol('isWritableObservable', ko.isWriteableObservable);
+ko.exportSymbol('observable.fn', observableFn);
+ko.exportProperty(observableFn, 'peek', observableFn.peek);
+ko.exportProperty(observableFn, 'valueHasMutated', observableFn.valueHasMutated);
+ko.exportProperty(observableFn, 'valueWillMutate', observableFn.valueWillMutate);

vendors/knockout/src/subscribables/observableArray.changeTracking.js

@@ -0,0 +1,158 @@
+var arrayChangeEventName = 'arrayChange';
+ko.extenders['trackArrayChanges'] = function(target, options) {
+    // Use the provided options--each call to trackArrayChanges overwrites the previously set options
+    target.compareArrayOptions = {};
+    if (options && typeof options == "object") {
+        ko.utils.extend(target.compareArrayOptions, options);
+    }
+    target.compareArrayOptions['sparse'] = true;
+
+    // Only modify the target observable once
+    if (target.cacheDiffForKnownOperation) {
+        return;
+    }
+    var trackingChanges = false,
+        cachedDiff = null,
+        changeSubscription,
+        spectateSubscription,
+        pendingChanges = 0,
+        previousContents,
+        underlyingBeforeSubscriptionAddFunction = target.beforeSubscriptionAdd,
+        underlyingAfterSubscriptionRemoveFunction = target.afterSubscriptionRemove;
+
+    // Watch "subscribe" calls, and for array change events, ensure change tracking is enabled
+    target.beforeSubscriptionAdd = function (event) {
+        if (underlyingBeforeSubscriptionAddFunction) {
+            underlyingBeforeSubscriptionAddFunction.call(target, event);
+        }
+        if (event === arrayChangeEventName) {
+            trackChanges();
+        }
+    };
+    // Watch "dispose" calls, and for array change events, ensure change tracking is disabled when all are disposed
+    target.afterSubscriptionRemove = function (event) {
+        if (underlyingAfterSubscriptionRemoveFunction) {
+            underlyingAfterSubscriptionRemoveFunction.call(target, event);
+        }
+        if (event === arrayChangeEventName && !target.hasSubscriptionsForEvent(arrayChangeEventName)) {
+            if (changeSubscription) {
+                changeSubscription.dispose();
+            }
+            if (spectateSubscription) {
+                spectateSubscription.dispose();
+            }
+            spectateSubscription = changeSubscription = null;
+            trackingChanges = false;
+            previousContents = undefined;
+        }
+    };
+
+    function trackChanges() {
+        if (trackingChanges) {
+            // Whenever there's a new subscription and there are pending notifications, make sure all previous
+            // subscriptions are notified of the change so that all subscriptions are in sync.
+            notifyChanges();
+            return;
+        }
+
+        trackingChanges = true;
+
+        // Track how many times the array actually changed value
+        spectateSubscription = target.subscribe(function () {
+            ++pendingChanges;
+        }, null, "spectate");
+
+        // Each time the array changes value, capture a clone so that on the next
+        // change it's possible to produce a diff
+        previousContents = [].concat(target.peek() || []);
+        cachedDiff = null;
+        changeSubscription = target.subscribe(notifyChanges);
+
+        function notifyChanges() {
+            if (pendingChanges) {
+                // Make a copy of the current contents and ensure it's an array
+                var currentContents = [].concat(target.peek() || []), changes;
+
+                // Compute the diff and issue notifications, but only if someone is listening
+                if (target.hasSubscriptionsForEvent(arrayChangeEventName)) {
+                    changes = getChanges(previousContents, currentContents);
+                }
+
+                // Eliminate references to the old, removed items, so they can be GCed
+                previousContents = currentContents;
+                cachedDiff = null;
+                pendingChanges = 0;
+
+                if (changes && changes.length) {
+                    target['notifySubscribers'](changes, arrayChangeEventName);
+                }
+            }
+        }
+    }
+
+    function getChanges(previousContents, currentContents) {
+        // We try to re-use cached diffs.
+        // The scenarios where pendingChanges > 1 are when using rate limiting or deferred updates,
+        // which without this check would not be compatible with arrayChange notifications. Normally,
+        // notifications are issued immediately so we wouldn't be queueing up more than one.
+        if (!cachedDiff || pendingChanges > 1) {
+            cachedDiff = ko.utils.compareArrays(previousContents, currentContents, target.compareArrayOptions);
+        }
+
+        return cachedDiff;
+    }
+
+    target.cacheDiffForKnownOperation = function(rawArray, operationName, args) {
+        // Only run if we're currently tracking changes for this observable array
+        // and there aren't any pending deferred notifications.
+        if (!trackingChanges || pendingChanges) {
+            return;
+        }
+        var diff = [],
+            arrayLength = rawArray.length,
+            argsLength = args.length,
+            offset = 0;
+
+        function pushDiff(status, value, index) {
+            return diff[diff.length] = { 'status': status, 'value': value, 'index': index };
+        }
+        switch (operationName) {
+            case 'push':
+                offset = arrayLength;
+            case 'unshift':
+                for (var index = 0; index < argsLength; index++) {
+                    pushDiff('added', args[index], offset + index);
+                }
+                break;
+
+            case 'pop':
+                offset = arrayLength - 1;
+            case 'shift':
+                if (arrayLength) {
+                    pushDiff('deleted', rawArray[offset], offset);
+                }
+                break;
+
+            case 'splice':
+                // Negative start index means 'from end of array'. After that we clamp to [0...arrayLength].
+                // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice
+                var startIndex = Math.min(Math.max(0, args[0] < 0 ? arrayLength + args[0] : args[0]), arrayLength),
+                    endDeleteIndex = argsLength === 1 ? arrayLength : Math.min(startIndex + (args[1] || 0), arrayLength),
+                    endAddIndex = startIndex + argsLength - 2,
+                    endIndex = Math.max(endDeleteIndex, endAddIndex),
+                    additions = [], deletions = [];
+                for (var index = startIndex, argsIndex = 2; index < endIndex; ++index, ++argsIndex) {
+                    if (index < endDeleteIndex)
+                        deletions.push(pushDiff('deleted', rawArray[index], index));
+                    if (index < endAddIndex)
+                        additions.push(pushDiff('added', args[argsIndex], index));
+                }
+                ko.utils.findMovesInArrayComparison(deletions, additions);
+                break;
+
+            default:
+                return;
+        }
+        cachedDiff = diff;
+    };
+};

vendors/knockout/src/subscribables/observableArray.js

@@ -0,0 +1,142 @@
+ko.observableArray = function (initialValues) {
+    initialValues = initialValues || [];
+
+    if (typeof initialValues != 'object' || !('length' in initialValues))
+        throw new Error("The argument passed when initializing an observable array must be an array, or null, or undefined.");
+
+    var result = ko.observable(initialValues);
+    ko.utils.setPrototypeOfOrExtend(result, ko.observableArray['fn']);
+    return result.extend({'trackArrayChanges':true});
+};
+
+ko.observableArray['fn'] = {
+    'remove': function (valueOrPredicate) {
+        var underlyingArray = this.peek();
+        var removedValues = [];
+        var predicate = typeof valueOrPredicate == "function" && !ko.isObservable(valueOrPredicate) ? valueOrPredicate : function (value) { return value === valueOrPredicate; };
+        for (var i = 0; i < underlyingArray.length; i++) {
+            var value = underlyingArray[i];
+            if (predicate(value)) {
+                if (removedValues.length === 0) {
+                    this.valueWillMutate();
+                }
+                if (underlyingArray[i] !== value) {
+                    throw Error("Array modified during remove; cannot remove item");
+                }
+                removedValues.push(value);
+                underlyingArray.splice(i, 1);
+                i--;
+            }
+        }
+        if (removedValues.length) {
+            this.valueHasMutated();
+        }
+        return removedValues;
+    },
+
+    'removeAll': function (arrayOfValues) {
+        // If you passed zero args, we remove everything
+        if (arrayOfValues === undefined) {
+            var underlyingArray = this.peek();
+            var allValues = underlyingArray.slice(0);
+            this.valueWillMutate();
+            underlyingArray.splice(0, underlyingArray.length);
+            this.valueHasMutated();
+            return allValues;
+        }
+        // If you passed an arg, we interpret it as an array of entries to remove
+        if (!arrayOfValues)
+            return [];
+        return this['remove'](function (value) {
+            return ko.utils.arrayIndexOf(arrayOfValues, value) >= 0;
+        });
+    },
+
+    'destroy': function (valueOrPredicate) {
+        var underlyingArray = this.peek();
+        var predicate = typeof valueOrPredicate == "function" && !ko.isObservable(valueOrPredicate) ? valueOrPredicate : function (value) { return value === valueOrPredicate; };
+        this.valueWillMutate();
+        for (var i = underlyingArray.length - 1; i >= 0; i--) {
+            var value = underlyingArray[i];
+            if (predicate(value))
+                value["_destroy"] = true;
+        }
+        this.valueHasMutated();
+    },
+
+    'destroyAll': function (arrayOfValues) {
+        // If you passed zero args, we destroy everything
+        if (arrayOfValues === undefined)
+            return this['destroy'](function() { return true });
+
+        // If you passed an arg, we interpret it as an array of entries to destroy
+        if (!arrayOfValues)
+            return [];
+        return this['destroy'](function (value) {
+            return ko.utils.arrayIndexOf(arrayOfValues, value) >= 0;
+        });
+    },
+
+    'indexOf': function (item) {
+        var underlyingArray = this();
+        return ko.utils.arrayIndexOf(underlyingArray, item);
+    },
+
+    'replace': function(oldItem, newItem) {
+        var index = this['indexOf'](oldItem);
+        if (index >= 0) {
+            this.valueWillMutate();
+            this.peek()[index] = newItem;
+            this.valueHasMutated();
+        }
+    },
+
+    'sorted': function (compareFunction) {
+        var arrayCopy = this().slice(0);
+        return compareFunction ? arrayCopy.sort(compareFunction) : arrayCopy.sort();
+    },
+
+    'reversed': function () {
+        return this().slice(0).reverse();
+    }
+};
+
+// Note that for browsers that don't support proto assignment, the
+// inheritance chain is created manually in the ko.observableArray constructor
+if (ko.utils.canSetPrototype) {
+    ko.utils.setPrototypeOf(ko.observableArray['fn'], ko.observable['fn']);
+}
+
+// Populate ko.observableArray.fn with read/write functions from native arrays
+// Important: Do not add any additional functions here that may reasonably be used to *read* data from the array
+// because we'll eval them without causing subscriptions, so ko.computed output could end up getting stale
+ko.utils.arrayForEach(["pop", "push", "reverse", "shift", "sort", "splice", "unshift"], function (methodName) {
+    ko.observableArray['fn'][methodName] = function () {
+        // Use "peek" to avoid creating a subscription in any computed that we're executing in the context of
+        // (for consistency with mutating regular observables)
+        var underlyingArray = this.peek();
+        this.valueWillMutate();
+        this.cacheDiffForKnownOperation(underlyingArray, methodName, arguments);
+        var methodCallResult = underlyingArray[methodName].apply(underlyingArray, arguments);
+        this.valueHasMutated();
+        // The native sort and reverse methods return a reference to the array, but it makes more sense to return the observable array instead.
+        return methodCallResult === underlyingArray ? this : methodCallResult;
+    };
+});
+
+// Populate ko.observableArray.fn with read-only functions from native arrays
+ko.utils.arrayForEach(["slice"], function (methodName) {
+    ko.observableArray['fn'][methodName] = function () {
+        var underlyingArray = this();
+        return underlyingArray[methodName].apply(underlyingArray, arguments);
+    };
+});
+
+ko.isObservableArray = function (instance) {
+    return ko.isObservable(instance)
+        && typeof instance["remove"] == "function"
+        && typeof instance["push"] == "function";
+};
+
+ko.exportSymbol('observableArray', ko.observableArray);
+ko.exportSymbol('isObservableArray', ko.isObservableArray);

vendors/knockout/src/subscribables/observableUtils.js

@@ -0,0 +1,22 @@
+ko.when = function(predicate, callback, context) {
+    function kowhen (resolve) {
+        var observable = ko.pureComputed(predicate, context).extend({notify:'always'});
+        var subscription = observable.subscribe(function(value) {
+            if (value) {
+                subscription.dispose();
+                resolve(value);
+            }
+        });
+        // In case the initial value is true, process it right away
+        observable['notifySubscribers'](observable.peek());
+
+        return subscription;
+    }
+    if (typeof Promise === "function" && !callback) {
+        return new Promise(kowhen);
+    } else {
+        return kowhen(callback.bind(context));
+    }
+};
+
+ko.exportSymbol('when', ko.when);

vendors/knockout/src/subscribables/subscribable.js

@@ -0,0 +1,208 @@
+
+ko.subscription = function (target, callback, disposeCallback) {
+    this._target = target;
+    this._callback = callback;
+    this._disposeCallback = disposeCallback;
+    this._isDisposed = false;
+    this._node = null;
+    this._domNodeDisposalCallback = null;
+    ko.exportProperty(this, 'dispose', this.dispose);
+    ko.exportProperty(this, 'disposeWhenNodeIsRemoved', this.disposeWhenNodeIsRemoved);
+};
+ko.subscription.prototype.dispose = function () {
+    var self = this;
+    if (!self._isDisposed) {
+        if (self._domNodeDisposalCallback) {
+            ko.utils.domNodeDisposal.removeDisposeCallback(self._node, self._domNodeDisposalCallback);
+        }
+        self._isDisposed = true;
+        self._disposeCallback();
+
+        self._target = self._callback = self._disposeCallback = self._node = self._domNodeDisposalCallback = null;
+    }
+};
+ko.subscription.prototype.disposeWhenNodeIsRemoved = function (node) {
+    this._node = node;
+    ko.utils.domNodeDisposal.addDisposeCallback(node, this._domNodeDisposalCallback = this.dispose.bind(this));
+};
+
+ko.subscribable = function () {
+    ko.utils.setPrototypeOfOrExtend(this, ko_subscribable_fn);
+    ko_subscribable_fn.init(this);
+}
+
+var defaultEvent = "change";
+
+// Moved out of "limit" to avoid the extra closure
+function limitNotifySubscribers(value, event) {
+    if (!event || event === defaultEvent) {
+        this._limitChange(value);
+    } else if (event === 'beforeChange') {
+        this._limitBeforeChange(value);
+    } else {
+        this._origNotifySubscribers(value, event);
+    }
+}
+
+var ko_subscribable_fn = {
+    init: function(instance) {
+        instance._subscriptions = { "change": [] };
+        instance._versionNumber = 1;
+    },
+
+    subscribe: function (callback, callbackTarget, event) {
+        var self = this;
+
+        event = event || defaultEvent;
+        var boundCallback = callbackTarget ? callback.bind(callbackTarget) : callback;
+
+        var subscription = new ko.subscription(self, boundCallback, function () {
+            ko.utils.arrayRemoveItem(self._subscriptions[event], subscription);
+            if (self.afterSubscriptionRemove)
+                self.afterSubscriptionRemove(event);
+        });
+
+        if (self.beforeSubscriptionAdd)
+            self.beforeSubscriptionAdd(event);
+
+        if (!self._subscriptions[event])
+            self._subscriptions[event] = [];
+        self._subscriptions[event].push(subscription);
+
+        return subscription;
+    },
+
+    "notifySubscribers": function (valueToNotify, event) {
+        event = event || defaultEvent;
+        if (event === defaultEvent) {
+            this.updateVersion();
+        }
+        if (this.hasSubscriptionsForEvent(event)) {
+            var subs = event === defaultEvent && this._changeSubscriptions || this._subscriptions[event].slice(0);
+            try {
+                ko.dependencyDetection.begin(); // Begin suppressing dependency detection (by setting the top frame to undefined)
+                for (var i = 0, subscription; subscription = subs[i]; ++i) {
+                    // In case a subscription was disposed during the arrayForEach cycle, check
+                    // for isDisposed on each subscription before invoking its callback
+                    if (!subscription._isDisposed)
+                        subscription._callback(valueToNotify);
+                }
+            } finally {
+                ko.dependencyDetection.end(); // End suppressing dependency detection
+            }
+        }
+    },
+
+    getVersion: function () {
+        return this._versionNumber;
+    },
+
+    hasChanged: function (versionToCheck) {
+        return this.getVersion() !== versionToCheck;
+    },
+
+    updateVersion: function () {
+        ++this._versionNumber;
+    },
+
+    limit: function(limitFunction) {
+        var self = this, selfIsObservable = ko.isObservable(self),
+            ignoreBeforeChange, notifyNextChange, previousValue, pendingValue, didUpdate,
+            beforeChange = 'beforeChange';
+
+        if (!self._origNotifySubscribers) {
+            self._origNotifySubscribers = self["notifySubscribers"];
+            self["notifySubscribers"] = limitNotifySubscribers;
+        }
+
+        var finish = limitFunction(function() {
+            self._notificationIsPending = false;
+
+            // If an observable provided a reference to itself, access it to get the latest value.
+            // This allows computed observables to delay calculating their value until needed.
+            if (selfIsObservable && pendingValue === self) {
+                pendingValue = self._evalIfChanged ? self._evalIfChanged() : self();
+            }
+            var shouldNotify = notifyNextChange || (didUpdate && self.isDifferent(previousValue, pendingValue));
+
+            didUpdate = notifyNextChange = ignoreBeforeChange = false;
+
+            if (shouldNotify) {
+                self._origNotifySubscribers(previousValue = pendingValue);
+            }
+        });
+
+        self._limitChange = function(value, isDirty) {
+            if (!isDirty || !self._notificationIsPending) {
+                didUpdate = !isDirty;
+            }
+            self._changeSubscriptions = self._subscriptions[defaultEvent].slice(0);
+            self._notificationIsPending = ignoreBeforeChange = true;
+            pendingValue = value;
+            finish();
+        };
+        self._limitBeforeChange = function(value) {
+            if (!ignoreBeforeChange) {
+                previousValue = value;
+                self._origNotifySubscribers(value, beforeChange);
+            }
+        };
+        self._recordUpdate = function() {
+            didUpdate = true;
+        };
+        self._notifyNextChangeIfValueIsDifferent = function() {
+            if (self.isDifferent(previousValue, self.peek(true /*evaluate*/))) {
+                notifyNextChange = true;
+            }
+        };
+    },
+
+    hasSubscriptionsForEvent: function(event) {
+        return this._subscriptions[event] && this._subscriptions[event].length;
+    },
+
+    getSubscriptionsCount: function (event) {
+        if (event) {
+            return this._subscriptions[event] && this._subscriptions[event].length || 0;
+        } else {
+            var total = 0;
+            ko.utils.objectForEach(this._subscriptions, function(eventName, subscriptions) {
+                if (eventName !== 'dirty')
+                    total += subscriptions.length;
+            });
+            return total;
+        }
+    },
+
+    isDifferent: function(oldValue, newValue) {
+        return !this['equalityComparer'] || !this['equalityComparer'](oldValue, newValue);
+    },
+
+    toString: function() {
+      return '[object Object]'
+    },
+
+    extend: applyExtenders
+};
+
+ko.exportProperty(ko_subscribable_fn, 'init', ko_subscribable_fn.init);
+ko.exportProperty(ko_subscribable_fn, 'subscribe', ko_subscribable_fn.subscribe);
+ko.exportProperty(ko_subscribable_fn, 'extend', ko_subscribable_fn.extend);
+ko.exportProperty(ko_subscribable_fn, 'getSubscriptionsCount', ko_subscribable_fn.getSubscriptionsCount);
+
+// For browsers that support proto assignment, we overwrite the prototype of each
+// observable instance. Since observables are functions, we need Function.prototype
+// to still be in the prototype chain.
+if (ko.utils.canSetPrototype) {
+    ko.utils.setPrototypeOf(ko_subscribable_fn, Function.prototype);
+}
+
+ko.subscribable['fn'] = ko_subscribable_fn;
+
+
+ko.isSubscribable = function (instance) {
+    return instance != null && typeof instance.subscribe == "function" && typeof instance["notifySubscribers"] == "function";
+};
+
+ko.exportSymbol('subscribable', ko.subscribable);
+ko.exportSymbol('isSubscribable', ko.isSubscribable);