@Christian-Ehrlicher : I created a bug report https://bugreports.qt.io/browse/QTBUG-80916 with a minimal viable example.

@SGaist said in Crashing when using QJSValue call: Did you check whether your application has a leak ? Yes, i have tested it for leaks. Does not seem to be the case. Is QJSValue.call to be used externally?

In the event that anyone else comes across this looking for a solution (like I was), Qt 5 and above can convert QByteArray to a Javascript ArrayBuffer. To do this, use toScriptValue: QJSEngine jsEngine = qjsEngine(this); QJSValueList args; args << title; args << jsEngine->toScriptValue(byteArray); callback.call(args);

@NewMoon see QTBUG-38181 It's a known limitation of QJSEngine. If you can, switch to QScriptEngine (QML).

@p3c0 Thank you for your help. The problem is that what I really want in the end is a way to catch errors thrown by C++ functions transparently to the user that writes JavaScript. So, the user can just write a script like: var X = myCppFunction(foo); var Y = myOtherCppFunction(bar); etc. And when it is executed (myEngine.evaluate) the errors are catched by the C++ code of my application. Something like: try { QJSValue theVal = myEngine.evaluate(the JavaScript script); if(theVal.isError) {//if there are errors in the JS code enter here} } catch( ) { // If there is an error in the Cpp functions called by the JS code enter here } I have seen in this post that this is not currently possible with QJSEngine. In addition, I have seen that a ticket is already open. Therefore, I will have to think something to get around and wait untill the functionality is implemented. Thank you for your help.

Hi @Mark81, As per the docs: Values must be simple constants; either strings (quoted and optionally within a call to QT_TR_NOOP), boolean values (true, false), numbers, or enumeration values (such as AlignText.AlignHCenter). So IMO a QColor cannot be assigned to the role myColor. And this in turn causes problem in the delegate.

@TheHawk Have you tried giving argument to addGraph()? I don't remember whether the default argument translate well to javascript. If that still doesn't work, you can try to make add a dummy QObject class with Q_INVOKABLE functions to your engine to see if the problem is in your code or some possible interaction with QCustomPlot

I managed using the following additional lines in CustomCode QString function = "test(1)"; QJSValue testfunction = myEngine.evaluate(function); qDebug() << testfunction.toString(); With my script CustomLogic.qs looking like this: function test(x) { var a = "tested!"; a = a + x.toString(); return a; } Returns "tested!1" in the application output

Hello, I had the same problem with showing the list of cameras in a ComboBox. the correct code is: ComboBox { id: cmbVideoCaptures model: QtMultimedia.availableCameras textRole: "displayName" valueRole: "deviceId" }

@bundickt said: @JKSH The output of qDebug() << data; is: QVariant(QJSValue, ) The output of data.value<QJSValue>().toVariant() is: QVariant(QVariantMap, QMap((key1, QVariant(QString, value1) ) ( key2 , QVariant(QString, value2) ) ) ) Ah, right. I thought the QML engine would automatically convert the QJSValue to a QVariantMap, but you had to do the conversion yourself. Thank you for sharing your findings!