Knockout.js print index of object in foreach

Question

This is probably quite simple but I can't seem to find it readily. In knockout.js, How would you print the index of an item in an observable array that you are iterating over using the foreach binding?

Answer 1

knockout 2.1 has added good new option $index. Here is example http://knockoutjs.com/documentation/foreach-binding.html

Answer 2

You can't. Not directly anyway. I use this function myself to add an index property to objects in my ObservableArrays:

    function indexSubscribe(array) {
        array.subscribe(function() {
            for (var i = 0, j = array().length; i < j; i++) {
                var item = array()[i];
                if (!item.index) {
                    item.index = ko.observable(i);  
                } else {
                    item.index(i);  
                }
            }
        }); 
   };

Then in my ViewModel, I can do something like this:

this.whatevers = ko.observableArray();
indexSubscribe(this.whatevers);