How do I remove "undefined" index in a Knockout observable array?

Question

            self.previewApplicationsScreeningQuestions = ko.computed(function () {
                return ko.utils.arrayMap(self.applications(), function (i) {
                    if (i.application.applicationKey == self.previewApplicationKey())
                        return i.application.applicantScreeningQuestionsAndResponses[0];
                });
            });

I declared a viewModel like this. What it does is, it basically loops through the "applications" viewModel and returns its "applicantScreeningQuestionsAndResponses[0]" object when a specific condition is met(not important in this question).

When I check the result of this in the console, it gives me.

[Object, undefined, undefined, undefined, undefined, undefined, undefined]

I just want to remove all undefined index and just leave one [Object] in the viewModel. How can I fix this?

EDIT:

            self.previewApplicationsScreeningQuestions = ko.computed(function () {
                return ko.utils.arrayMap(self.applications(), function (i) {
                    if (i.application.applicationKey == self.previewApplicationKey())
                        var arr = i.application.applicantScreeningQuestionsAndResponses[0];
                });
                var newArr = new Array();
                for (var i = 0; i < arr.length; i++) {
                    if (arr[i]) {
                        newArr.push(arr[i]);

                    }

                }
                return newArr;
            });

This returns all 'undefined'

Possible duplicate of [Remove empty elements from an array in Javascript](https://stackoverflow.com/questions/281264/remove-empty-elements-from-an-array-in-javascript) — Meirion Hughes, Jun 16 '17 at 22:39
I tried the link and implemented in my code, but it just returns all undefined — Dukakus17, Jun 16 '17 at 22:49
you're updated code returns before newArr is returned - c&p error? — Meirion Hughes, Jun 16 '17 at 23:07

score 0 · Accepted Answer · answered Jun 19 '17 at 10:13

you can write somting like below:

 self.previewApplicationsScreeningQuestions = ko.computed(function () {
            return ko.utils.arrayMap(self.applications(), function (i) {
                if (i.application.applicationKey == self.previewApplicationKey() && i.application.applicantScreeningQuestionsAndResponses[0]!=undefined)
                    return i.application.applicantScreeningQuestionsAndResponses[0];
            });
        });

How do I remove "undefined" index in a Knockout observable array?

1 Answers1