[Development] Using semicolons in JS (QML)

Kai Koehne Kai.Koehne at qt.io
Fri Sep 30 14:19:09 CEST 2016


It’s Friday, so time for some bikeshedding ;)

As you might know, the semicolon as a statement separator in JavaScript is optional. That is, most of the time you can just separate commands
by newlines. There are a few pathological cases [1] though where a semicolon is needed. It seems the JavaScript world is divided on the topic
whether to use semicolons by default though.

Now I do not care that much about JavaScript as a language, but I do care about consistency in the Qt documentation and examples. Unfortunately
we didn’t seem to have made a call so far what to prefer. Even our minimal “QML coding conventions” at http://doc.qt.io/qt-5/qml-codingconventions.html
feature a semicolon in places, and in others no semicolon.

To make a proposal: Let’s use semicolons in imperative JS parts of QML in our examples and documentation.
Apart from being on the safe side regarding some pathological cases, it also makes the difference between declarative QML bindings  and
imperative JS code more explicit.

Now I do realize that the right side of QML bindings is actually JavaScript. But no, I do not want to propose that now every binding ends with a ‘;’.
A good rule of thumb might be that semicolons should be used inside either function X() {} or OnSignalHandler: {} blocks, or in .js files.



[1]: See e.g. http://benalman.com/news/2013/01/advice-javascript-semicolon-haters/


Kai Köhne, Senior Manager R&D | The Qt Company

The Qt Company GmbH, Rudower Chaussee 13, D-12489 Berlin
Geschäftsführer: Mika Pälsi, Juha Varelius, Mika Harjuaho. Sitz der Gesellschaft: Berlin, Registergericht: Amtsgericht Charlottenburg, HRB 144331 B

Qt World Summit 2016 | Pier 27, San Francisco, CA
Experience Exponential Potential on October 18-20

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.qt-project.org/pipermail/development/attachments/20160930/1e8cd714/attachment.html>

More information about the Development mailing list