Doing `F; class F{};` makes `F` both an undefined variable, and an already defined identifier. Is this a bug?

Asked Jan 24 '17 at 02:42

Active Jan 24 '17 at 02:55

Viewed 122 times

Doing F; class F{} on the chrome console gives a reference error (F is not defined), but after that, doing class F{} again yields Identifier 'F' has already been declared, while F; yields a reference error (even typeof F gives a reference error!).

Is this a bug or intended behaviour?

edited Jan 24 '17 at 02:55

asked Jan 24 '17 at 02:42

YoTengoUnLCD

1

it's a bug in your code if you're doing that :p – Jaromanda X Jan 24 '17 at 02:44
It makes sense because of the “temporal dead zone” (the reason `(function () { return typeof X; class X {} })()` is a `ReferenceError` instead of `"undefined"`), but probably isn’t the ideal behaviour for a console. – Ry- Jan 24 '17 at 02:50
Works fine for me. [1]: https://i.stack.imgur.com/Qe3px.png – Brendan Long Jan 24 '17 at 02:52
@BrendanLong You haven't done `F; class F{};` (same line!). – YoTengoUnLCD Jan 24 '17 at 02:54
`F` `Enter`, then `class F{}` `Enter` should not log `Identifier 'F' has already been declared` `SyntaxError`. What are you trying to determine? – guest271314 Jan 24 '17 at 02:55
What is the purpose of the exercise? – guest271314 Jan 24 '17 at 03:15

Doing `F; class F{};` makes `F` both an undefined variable, and an already defined identifier. Is this a bug?

0 Answers0