Question

This is sample code. I want to break (or continue) knockout’s ko.util.arrayForEach.

ko.utils.arrayForEach(items, function (item) {
    if (...) break;
    if (...) continue;
}

Answer 1

Looks like you can’t. Here’s the source of arrayForEach (from utils.js on the KO GitHub page)

arrayForEach: function (array, action) {
    for (var i = 0, j = array.length; i < j; i++)
        action(array[i]);
},

However Knockout provides ko.utils.arrayFirst that will execute a function against each item in our array and return the first item where the function evaluates to true. Similar to the filteredItems computed observable, we can create one that returns the first match from our search field:

//identify the first matching item by name
viewModel.firstMatch = ko.computed(function() {
    var search = this.search().toLowerCase();
    if (!search) {
        return null;
    } else {
        return ko.utils.arrayFirst(this.filteredItems(), function(item) {
            return ko.utils.stringStartsWith(item.name().toLowerCase(), search);
        });
    }
}, viewModel);

More details can be found here http://www.knockmeout.net/2011/04/utility-functions-in-knockoutjs.html