QJSValue engine() deprecated in Qt5.15

Daes

Hello,

I am using C++ to interpret some callable QJSValue coming from QML as callback functions.
Currently, i was using the engine() function to add parameters to those function like this:

QJsValueList args;
args << callable.engine()->toScriptValue(aValue);
callcable.call(args);

Now the engine() function is deprecated.
How can i get the callable engine, as if i use an other engine to create the value, it is not possible to use the call(..) function with it?

Kai Nickel

I do not have a real answer for that. But I also use QJSValue callbacks a lot, and I think that this is a very important pattern (which is not so well supported by Qt unfortunately).

Im my case, the C++ function is always a method of a QObject exposed to QML (either via singleton or it is instantiated from QML). In both cases, you can get the engine via qjsEngine() on that object:

class App : public QObject {
    Q_OBJECT
    Q_INVOKABLE void doSomethingAsync(QJSValue callback) {
        auto engine = qjsEngine(this);
        ....
    }
};

Daes

@Kai-Nickel said in QJSValue engine() deprecated in Qt5.15:

qjsEngine

Thanks, Kai.
I didn't know the qjsEngine function.
I am in the same use case as you, so that should do the trick.