Bugfix: put back the knockout bindings if/ifnot as they are in use

vendors/knockout/src/binding/defaultBindings/ifIfnot.js

@@ -0,0 +1,72 @@
+(() => {
+
+// Makes a binding like with or if
+function makeIfBinding(bindingKey, isNot) {
+    ko.bindingHandlers[bindingKey] = {
+        'init': (element, valueAccessor, allBindings, viewModel, bindingContext) => {
+            var didDisplayOnLastUpdate, savedNodes, contextOptions = {}, completeOnRender, needAsyncContext, renderOnEveryChange;
+
+            completeOnRender = allBindings.get("completeOn") == "render";
+            needAsyncContext = completeOnRender || allBindings['has'](ko.bindingEvent.descendantsComplete);
+
+            ko.computed(() => {
+                var value = ko.utils.unwrapObservable(valueAccessor()),
+                    shouldDisplay = !isNot !== !value, // equivalent to isNot ? !value : !!value,
+                    isInitial = !savedNodes,
+                    childContext;
+
+                if (!renderOnEveryChange && shouldDisplay === didDisplayOnLastUpdate) {
+                    return;
+                }
+
+                if (needAsyncContext) {
+                    bindingContext = ko.bindingEvent.startPossiblyAsyncContentBinding(element, bindingContext);
+                }
+
+                if (shouldDisplay) {
+                    if (renderOnEveryChange) {
+                        contextOptions['dataDependency'] = ko.computedContext.computed();
+                    }
+
+                    if (ko.computedContext.getDependenciesCount()) {
+                        childContext = bindingContext['extend'](null, contextOptions);
+                    } else {
+                        childContext = bindingContext;
+                    }
+                }
+
+                // Save a copy of the inner nodes on the initial update, but only if we have dependencies.
+                if (isInitial && ko.computedContext.getDependenciesCount()) {
+                    savedNodes = ko.utils.cloneNodes(ko.virtualElements.childNodes(element), true /* shouldCleanNodes */);
+                }
+
+                if (shouldDisplay) {
+                    if (!isInitial) {
+                        ko.virtualElements.setDomNodeChildren(element, ko.utils.cloneNodes(savedNodes));
+                    }
+
+                    ko.applyBindingsToDescendants(childContext, element);
+                } else {
+                    ko.virtualElements.emptyNode(element);
+
+                    if (!completeOnRender) {
+                        ko.bindingEvent.notify(element, ko.bindingEvent.childrenComplete);
+                    }
+                }
+
+                didDisplayOnLastUpdate = shouldDisplay;
+
+            }, null, { disposeWhenNodeIsRemoved: element });
+
+            return { 'controlsDescendantBindings': true };
+        }
+    };
+    ko.expressionRewriting.bindingRewriteValidators[bindingKey] = false; // Can't rewrite control flow bindings
+    ko.virtualElements.allowedBindings[bindingKey] = true;
+}
+
+// Construct the actual binding handlers
+makeIfBinding('if');
+makeIfBinding('ifnot', true);
+
+})();