Falsy

In JavaScript, any expression or statement that expects a boolean value will work with a truthy or falsy value, so the fact that && does not always evaluate to true or false does not cause practical problems.

However, in the second case, both '0' and the empty string () are falsy (in other words, they behave like false) and are therefore equal with respect to ==.

If the first operand (which comes before the question mark--doIt, in this example) is truthy, the expression evaluates to the second operand (between the question mark and colon), and if it's falsy, it evaluates to the third operand (after the colon).