Question

I have declared 2 observable arrays as following in my code

self.versionDataByProduct = ko.observableArray([]);
self.copiedSavedVersionData = ko.observableArray([]);

When i save data i copy all value from self.versionDataByProduct into self.copiedSavedVersionData like below

 self.copiedSavedVersionData(self.versionDataByProduct());

Then i try to compare 2 observable array on button event called compareArray like below

 this.compareArray = function () {
        debugger;
        var results = [];
        var differences = ko.utils.compareArrays(self.versionDataByProduct(), self.copiedSavedVersionData());
        ko.utils.arrayForEach(differences, function (difference) {
            if (difference.status === "deleted") {
                results.push(difference.value);
            }
        });
        return results;
    };

But this doesnt work. Because after i copy one observable array to other and do some modification in observable array then it automatically updates other. I dont want that. I want my observable array self.copiedSavedVersionData to remain as is after it is copied. How can i achieve it? I am just doing it track if i have done any changes. If array is changed then i will enable button in my code. Currently i dont know how do i go about dirty tracking so found this alternative but not working. Please help.

Answer 1

You can use slice function for this:

 self.copiedSavedVersionData(self.versionDataByProduct().slice(0));

In that case ko will clone array.