Please see: Knockout.js Performance Gotcha #2 – Manipulating observableArrays A better pattern is to get a reference to our underlying array, push to it, then call .valueHasMutated(). Now, our subscribers will only receive one notification indicating that the array has changed.
$index is an observable, and observables are functions. When you use observables in an expression you must use the () form to access the value. <!– ko if: $index() === 0 –>
ko.subscribable.fn.subscribeChanged = function (callback) { var oldValue; this.subscribe(function (_oldValue) { oldValue = _oldValue; }, this, ‘beforeChange’); this.subscribe(function (newValue) { callback(newValue, oldValue); }); }; Use the above like this: MyViewModel.MyObservableProperty.subscribeChanged(function (newValue, oldValue) { });
You wont be able to do this from the client side because of the Same Origin Policy set by the browsers. You wont be able to get much information from the iFrame other than basic properties like its width and height. Also, google sets in its response header an ‘X-Frame-Options’ of SAMEORIGIN. Even if you … Read more
Note: As of jQuery 1.7, the .live() method is deprecated. Use .on() to attach event handlers. Users of older versions of jQuery should use .delegate() in preference to .live(). I’m working on the same thing (knockout + jquery mobile). I’m trying to write a blog post about what I’ve learned but here are some pointers … Read more
to access the index of the parent object use $parentContext.$index() rather than $parent.index()
There are a couple different ways that you can handle this type of code. with an if/ifnot combination like you are now. This works fine and is not terribly verbose. Michael Best’s switch/case binding (https://github.com/mbest/knockout-switch-case) is quite flexible and can let you easily handle this and more complicated ones (more states than true/false). Another option … Read more
Actually you want to find whether the event is triggered by user or program , and its obvious that event will trigger while initialization. The knockout approach of adding subscription won’t help in all cases, why because in most of the model will be implemented like this init the model with undefined data , just … Read more
Knockout includes a function called ko.isObservable(). You can call it like ko.isObservable(vm[key]). Update from comment: Here is a function to determine if something is a computed observable: ko.isComputed = function (instance) { if ((instance === null) || (instance === undefined) || (instance.__ko_proto__ === undefined)) return false; if (instance.__ko_proto__ === ko.dependentObservable) return true; return ko.isComputed(instance.__ko_proto__); // … Read more
This problem was happening because I was trying to bind an HTML element before it was created. My script was loaded on top of the HTML (in the head) but it needed to be loaded at the bottom of my HTML code (just before the closing body tag). Thanks for your attention James Allardice. A … Read more