Does Undefined Evaluate to False?

A falsy value is something which evaluates to FALSE, for instance when checking a variable. There are only six falsey values in JavaScript: undefined , null , NaN , 0 , "" (empty string), and false of course.

Does undefined evaluate to false JS?

A falsy value is something which evaluates to FALSE, for instance when checking a variable. There are only six falsey values in JavaScript: undefined , null , NaN , 0 , "" (empty string), and false of course.

Does undefined evaluate to true or false?

So undefined really means undefined. Not False, not True, not 0, not empty string. So when you compare undefined to anything, the result is always false, it is not equal to that.