Modify the getAttribute value if it is null

I'm currently working on a project where I need to compile the answers selected in a quiz into a document.

However, I've encountered a roadblock when certain questions are skipped based on previous responses. This leads to an error message:

Uncaught TypeError: Cannot read properties of null (reading 'getAttribute')

I'm seeking guidance on how to modify my code so that it assigns a value of "N/A" when a question is skipped. Below is my attempted solution, but it hasn't worked as expected:

var oldValue = document.querySelector(".quiz_selected_answer input[name='question-2']").getAttribute('data-value');
            var newValue; 
            if (!oldValue) { 
                newValue =  
                "N/A"; 
            } else { 
                newValue = oldValue; 
            }

Any assistance from the community would be greatly appreciated. Thank you for your help.

javascript

Answer №1

If the error occurs at this specific line:

var previousValue = document.querySelector(".quiz_selected_answer input[name='question-2']").getAttribute('data-value');

No matter what modifications are made subsequent to this line, the error will block the code from progressing beyond that point.

An alternative solution would be to utilize optional chaining:

var previousValue = document.querySelector(".quiz_selected_answer input[name='question-2']")?.getAttribute('data-value');
//                                                             indicated here >----------------------^

This way, instead of triggering an error, it would simply assign undefined to previousValue, which is considered "falsy" and should suffice for the remainder of the code execution.

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