What is the better way to check if a variable is undefined?

Asked Jul 05 '19 at 05:53

Active Jul 05 '19 at 05:56

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In my application, I have the following code.

if (values && (values.cardNumber !== undefined)) {

But I have seen in some places where it looks something like this.

if (values && typeof (values.cardNumber !== 'undefined')) {

Which is the better and more secure approach to check if something is undefined??

asked Jul 05 '19 at 05:53

Shashika Virajh

3

You should keep it the way it is. `typeof` offers no advantage in practice. (Also, that would be the wrong way to use it.) Relevant answer if you’re looking for a lot of detail (ignore the accepted one): https://stackoverflow.com/questions/27509/detecting-an-undefined-object-property/22053469#22053469 – Ry- Jul 05 '19 at 05:54
Thanks RY for the info – Shashika Virajh Jul 05 '19 at 10:23

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