What is the best way to check if a property is undefined?

I’m now using this logic because the input should be a string:

But basically I’m looking for a check “is defined” or “not defined”, but can’t seem to find it.

Hello, @Michiel_Prins1.

I understand correctly, you want to check the String value for null?
Correct me if this is not the case.

Regards, Nikita.

No, I want to know if a property is undefined.

When you have an input value bound to a property, that property is undefined until you enter at least one character in that input.

Although the Codeless is built on JS, but in some cases, we purposely avoiding paradigms and characteristic features of this language.

undefined - is one of them.

Here a little workaround hot to check is property undefined(not nullish value like empty string,null,false)


Regards, Dima


upd: solution above not right, because we use not strict equal(===)

Here is a right one