Knockoutjs computed passing parameters

Question

I am wondering if it is possible with knockoutjs to pass arguments when binding.

I am binding a list of checkboxes and would like to bind to a single computed observabl

Answer 1

The accepted answer is decent, but if you have a function that generates a ko.computed for each checkbox, you are adding unnecessary overhead with multiple anonymous computed observables, which adds up quickly when your checkbox lists exceed 4-5 options.

This is a simpler implementation of a bitwise scenario, but the computed function can be whatever need be.

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Script:

var vm = function() {
    var vm = this;

    this.checkedList = ko.observableArray();
    this.bitwiseValue = ko.computed({
        read: function () {
            return vm.checkedList().reduce(function (prev, curr) {
                return prev | curr;
            }, 0);
        },
        write: function (myVal) {
            vm.checkedList.removeAll();
            var placeValue = 1;

            while(myVal > 0) {
                if((myVal % 2) == 1) {
                    alert(placeValue);
                    vm.checkedList.push(placeValue.toString());
                }

                myVal = myVal >>> 1;                    
                placeValue = placeValue * 2;
            }
        }
    }, this);
}

ko.applyBindings(vm);

Example fiddle here: http://jsfiddle.net/i_vargas3/RYQgg/