They are very similar. The difference is that pureComputed has some performance optimizations, and tries to prevent memory leaks, by being smart about who’s tracking its changes. You can safely replace computed with pureComputed in a lot of cases. The function inside the computed should follow this: 1.Evaluating the computed observable should not cause any … Read more
Knockout 2.0 has two functions that you could use for this purpose. ko.dataFor and ko.contextFor take in a node and return either the Knockout data that would be available to it for binding at that scope (dataFor) or the entire binding context at that scope (contextFor), which includes $data, $parent, $parents, and $root. So, you … Read more
This will combine the two arrays and return the combined list. However, it is not a computed observable array (don’t know if that is even possible), but a regular computed observable. self.masterList = ko.computed(function() { return this.listA().concat(this.listB()); }, this);
You can do something like: <ul data-bind=”foreach: people”> <li> <input type=”checkbox” data-bind=”checkedValue: id, checked: $parent.selectedPeople”> </li> </ul> With this kind of ViewModel: var viewModel = { people: ko.observableArray(listOfPeople), selectedPeople: ko.observableArray() }; The value attribute controls what the checked binding adds/removes from an array when it is bound against an array. You could also write a … Read more
Steve (the creator of Knockout) explained the difference on his blog: I’m very familiar with Rx for JavaScript, having recently used it heavily on a big project, and in fact aspects of the design of Knockout are made with my Rx experiences in mind. The key difference between Knockout’s implementation of the observer pattern and … Read more
Errors from jsfiddle pages do get sent to your browser. As for your error, try this: <span data-bind=”text: clins().length”> This turns the observableArray into an array and uses the array’s length property. See the updated the jsfiddle as well.
You just need to put double quotes around it: <input data-bind=’text: Title, attr: {“data-id”: “Events[” + viewModel.events.indexOf($data) + “].Title”}’/>
Also knockout observableArray has interesting methods. Call removeAll to clear all items. Look at official site observable array manual. self.mycertificates = ko.observableArray([‘C1’, ‘C2’]); self.mycertificates.removeAll();
Have a look at Knockout-Validation which cleanly setups and uses what’s described in the knockout documentation. Under: Live Example 1: Forcing input to be numeric You can see it live in Fiddle UPDATE: the fiddle has been updated to use the latest KO 2.0.3 and ko.validation 1.0.2 using the cloudfare CDN urls To setup ko.validation: … Read more
You can use the css binding. It can be used two ways. Either with a dynamic class (or list of classes): <li data-bind=”css: name”></li> or with individual classes bound against truthy/falsy values to indicate whether that are should be added/removed from the element: <li data-bind=”css: { classOne: hasClassOne, classTwo: hasClassTwo }”></li>