knockout arraygetdistinctvalues of objects

Question

I want to use ko.utils.arrayGetDistinctValues like in this fiddle on more than one property in an array so I map the array to an array of just the two propertie

Answer 1

arrayGetDistinctValues only works with primitive values. For objects, you'll need a different approach. Here's a version that works.

viewModel.uniqueCategories = ko.dependentObservable(function() {
    var seen = [];
    return viewModel.justCategories().filter(function(n) {
        return seen.indexOf(n.catid) == -1 && seen.push(n.catid);
    });
});

http://jsfiddle.net/mbest/dDA4M/2/

Answer 2

As an update to Michael Best's answer, here is something using more recent KnockoutJS v3 code conventions (e.g. dependentObservable = computed and using arrayFilter method):

var uniqueSizes = ko.computed({read: function() {
    var seen = [];
    return ko.utils.arrayFilter(viewModel.collection.vendorGearFilters(), function(f) {
        return seen.indexOf(f['size_abbr']()) == -1 && seen.push(f['size_abbr']());
    });
}, deferEvaluation: true})