What will be the output of the following code, and why does the unary plus operator behave this way in JavaScript?

The unary plus operator (+) attempts to convert its operand into a number:

1. +true → 1
    Boolean true is converted to number 1.
2. +"" → 0
    Empty string is converted to 0.
3. +null → 0
 null is converted to 0.
4. +undefined → NaN
 undefined cannot be converted into a meaningful number, resulting in NaN.