Remove more unused Knockout code

vendors/knockout/src/subscribables/dependentObservable.js

@@ -76,10 +76,6 @@ ko.computed = ko.dependentObservable = function (evaluatorFunctionOrOptions, eva
         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;
@@ -210,19 +206,7 @@ var computedFn = {
         }
     },
     subscribeToDependency: function (target) {
-        if (target._deferUpdates) {
-            var dirtySub = target.subscribe(this.markDirty, this, 'dirty'),
-                changeSub = target.subscribe(this.respondToChange, this);
-            return {
-                _target: target,
-                dispose: () => {
-                    dirtySub.dispose();
-                    changeSub.dispose();
-                }
-            };
-        } else {
-            return target.subscribe(this.evaluatePossiblyAsync, this);
-        }
+        return target.subscribe(this.evaluatePossiblyAsync, this);
     },
     evaluatePossiblyAsync: function () {
         var computedObservable = this,

vendors/knockout/src/subscribables/extenders.js

@@ -28,40 +28,10 @@ ko.extenders = {
             method = options['method'];
         }
 
-        // rateLimit supersedes deferred updates
-        target._deferUpdates = false;
-
         limitFunction = typeof method == 'function' ? method : method == 'notifyWhenChangesStop' ?  debounce : throttle;
         target.limit(callback => limitFunction(callback, timeout, options));
     },
 
-    'deferred': (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(callback => {
-                var handle,
-                    ignoreUpdates = false;
-                return () => {
-                    if (!ignoreUpdates) {
-                        ko.tasks.cancel(handle);
-                        handle = ko.tasks.schedule(callback);
-
-                        try {
-                            ignoreUpdates = true;
-                            target['notifySubscribers'](undefined, 'dirty');
-                        } finally {
-                            ignoreUpdates = false;
-                        }
-                    }
-                };
-            });
-        }
-    },
-
     'notify': (target, notifyWhen) => {
         target["equalityComparer"] = notifyWhen == "always" ?
             null :  // null equalityComparer means to always notify

vendors/knockout/src/subscribables/observable.js

@@ -32,10 +32,6 @@ ko.observable = initialValue => {
     // Inherit from 'observable'
     ko.utils.setPrototypeOfOrExtend(observable, observableFn);
 
-    if (ko.options['deferUpdates']) {
-        ko.extenders['deferred'](observable, true);
-    }
-
     return observable;
 }
 
@@ -76,7 +72,6 @@ ko.isWriteableObservable = instance => {
 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);

vendors/knockout/src/subscribables/observableArray.js

@@ -66,7 +66,7 @@ if (ko.utils.canSetPrototype) {
 // 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"], methodName => {
+["pop", "push", "reverse", "shift", "sort", "splice", "unshift"].forEach(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)
@@ -81,7 +81,7 @@ ko.utils.arrayForEach(["pop", "push", "reverse", "shift", "sort", "splice", "uns
 });
 
 // Populate ko.observableArray.fn with read-only functions from native arrays
-ko.utils.arrayForEach(["slice"], methodName => {
+["slice"].forEach(methodName => {
     ko.observableArray['fn'][methodName] = function () {
         var underlyingArray = this();
         return underlyingArray[methodName].apply(underlyingArray, arguments);

vendors/knockout/src/subscribables/subscribable.js

@@ -166,10 +166,9 @@ var ko_subscribable_fn = {
             return this._subscriptions[event] && this._subscriptions[event].length || 0;
         }
         var total = 0;
-        ko.utils.objectForEach(this._subscriptions, (eventName, subscriptions) => {
-            if (eventName !== 'dirty')
-                total += subscriptions.length;
-        });
+        ko.utils.objectForEach(this._subscriptions, (eventName, subscriptions) =>
+            total += subscriptions.length
+        );
         return total;
     },