Calling JavaScript function from C++ ?

[SPlatten]

From JavaScript I can call a C++ routine, I've done this already, now what I want to do is be able to call a JavaScript routine from C++. I have a C++ routine called:

Q_INVOKABLE void registerDecoder(const QJsonObject& crobjJSON);

In the passed constant reference JSON passed I have:

{"decoder":"simon.js@decodeFIOrdy"
  ,"match":"mdFileIO"
, "member":"source"}

In my C++ routine:

void clsScriptHelper::registerDecoder(const QJsonObject& crobjJSON) {
    QJsonObject::const_iterator citrDecoder = crobjJSON.find(clsJSON::mscszDecoder)
                               ,citrMatch = crobjJSON.find(clsJSON::mscszMatch)
                               ,citrMember = crobjJSON.find(clsJSON::mscszMember);
    if ( citrDecoder == crobjJSON.end()
      || citrMatch == crobjJSON.end()
      || citrMember == crobjJSON.end() ) {
        return;
    }
    QString strDecoder = citrDecoder.value().toString()
           ,strMatch = citrMatch.value().toString()
           ,strMember = citrMember.value().toString();
    if ( strDecoder.isEmpty() == true
      || strMatch.isEmpty() == true
      || strMember.isEmpty() == true ) {
        return;
    }
    QStringList slstDecoder = strDecoder.split(clsScriptHelper::msccDecoderDelimiter);

    if ( slstDecoder.length() != SDA_COUNT ) {
        return;
    }
    QString strFile = slstDecoder[SDA_FILE]
           ,strFunction = slstDecoder[SDA_FUNCTION];
}

How do I call the decoder function which is specified in the JSON from C++ ? strFile contains the script file name, strFunction contains the function name.

I found this:
https://forum.qt.io/topic/67039/calling-js-functions-in-loaded-components-from-c

And am in the process of seeing if I can use it.

[SPlatten]

I think I've resolved this by calling the instance of QJSEngine my application is using and calling the evaluate function.