如何删除可观察的数组中的“未定义”索引？

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'

Answer 1

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];
            });
        });