@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.

Thanks for the reply, I will take this to the mailing list!

@zerocom I had the same issue and your comment helped me to solve it. but this solution seems to be working for predefined number of arguments for invokable functions. is there any way to create an invokable function with variable argument number similar to what we used to do by QScriptContext?

@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

Hi. I'm not sure I understand what you mean, but take a look here:

http://doc.qt.io/qt-5/qtqml-javascript-imports.html#imports-within-javascript-resources

It might help.

Thank you for your answers.

Richardo, unfortunately none of those work: an error value is returned, not thrown.

As a workaround I use return values at the moment. I will suggest adding a QJSEngine::throwError() method to the mailing list.