Underscore adaptation of '_.where' for knockout

gistfile1.js

_.mixin({
    koMatches: function (attrs) {
        return function (obj) {
            if (obj == null){
                return _.isEmpty(attrs);
            }
            if (obj === attrs){
                return true;
            }
            for (var key in attrs) {
                if (typeof(obj[key]) == 'function') {
                    if (attrs[key] !== obj[key].call()) {
                        return false;
                    }
                } else {
                    if (attrs[key] !== obj[key]) {
                        return false;
                    }
                }
            }
            return true;
        }
    },
    koWhere: function (obj, attrs) {
        var results = [];
        var predicate = _.koMatches(attrs);
        if (obj == null){
            return results;
        }
        _.each(obj, function (value, index, list) {
            if (predicate.call(attrs, value)){
                results.push(value);
            }
        });
        return results;
    }
});

gistfile2.js

function Test(){
    this.attr = ko.observableArray()
}

var hede = new Test();
ko.applyBindings(hede);

hede.attr.push({"key": ko.observable(1)});
hede.attr.push({"key": ko.observable(2)});

console.log(_.koWhere(hede.attr(), {"key":2}));
  [>object]