[Interest] Kicking out QtScript completely

Frederik Gladhorn frederik.gladhorn at theqtcompany.com
Wed Mar 18 17:22:06 CET 2015

Hello all,

thanks for all the feedback, it's very much appreciated.
The discussion has sparked quite a few discussions here in Oslo and we see 
that we have some way to cover when it comes to getting QJSEngine up to the 
level of what QtScript offers currently.

We think being able to run non-gui applications is important, that's why we 
have a clean separation between the QML and Quick libraries. Using only the 
QML library there are no UI dependencies and QJSEngine is available as a pure 
JS engine without forcing any QML on anyone.

We still think it's the right way forward - maintaining one engine and keeping 
it running well, instead of trying to deal with JSC, see Thiago's mails for 
the reasoning behind that (plus the one in WebEngine which is unrelated to 
this discussion).

The deprecation is just the label that reflects reality for QtScript. There is 
no work being done on the module actively.

The focus will now be to get the missing features in place in QJSEngine. Most 
of them hopefully by the time of the 5.6 release, to get the offering on par.
It would be helpful to get a list of features that really need to be there, 
currently from what I understand the most urgent ones are:
- instantiating QObjects from JS
- exposing individual native functions to JS
- debugging API
The good thing is that a lot of the work is already done in QJSEngine, it's 
simply not exposed in the API yet.

To re-iterate: QtScript is not going away, especially not before we have a 
full replacement including more porting documentation. But don't expect active 
development of the module to happen either. For many simple use cases, 
QJSEngine can act as drop in replacement by the way, so we do care about the 
migration path and try to keep API compatible where it is possible.


On Tuesday, March 17, 2015 03:33:52 PM Christian Dähn wrote:
> Hi folks,
> as stated inside the Qt Blog the devs just decided to drop any
> QtScript support within the next release - without any replacement
> for users NOT USING QML / console apps!
> This will even break any backend app running without gui,
> because starting with Qt 5.6 only scripting by using the QML
> module is supported and all support for QtScript will be completely
> dropped without any non-GUI replacement!!!!
> I already had big pains within the last years when the scripting
> APIs changed and there where big problems - which got solved with
> the neat an modular QtScript. This is even for me the base of
> industrial grade apps running on dozens of servers/clusters
> and must be maintained for many years.
> So am I the only one who cares about QtScript?
> Am I the only one who still doesn't use (and even want) QML?
> Regards,
> Chris
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