The “unexpected ++” error in jslint [duplicate]

Answer 1

The real problem of the ++ operator is that it is an operator with side effects and thus it is totally opposed to the principle of functional programming.

The "functional" way to implement i++ would be i = i + 1 where you explicitly reassign the variable with no side effects and then use it.

The possibility of confusion is that ++ does two things by adding a value AND reassigning it to the variable.