4. QJSEngine and SyntaxError ?

QJSEngine and SyntaxError ?


  • I am using the QJSEngine, I added a global to the object:

        QJSValue objGlobal = pobjScriptEng->globalObject();

    pobjScriptEng is a pointer to an instance of QJSEngine.

    I have a map of globals, the map type definition:

        std::map<QString, QString> mpGlobals;

    I iterate through the globals map adding them to the engine:

        for( mpGlobals::iterator itr=rmpGlobals.begin(); itr!=rmpGlobals.end(); itr++ ) {
        QString strName(itr->first);

        if ( objGlobal.hasProperty(strName) == false ) {
            QString strData(itr->second);
            QJSValue result = pobjScriptEng->evaluate(strData);
            objGlobal.setProperty(strName, result);
        }
    }

    rmpGlobals is a reference to the globals map.

    I have a script which includes a reference to a global, the global is called "db" and is a JSON object that contains:

        {"db":"test","host":"localhost","usr":"root","pass":"123456"}

    I added some debug to the loop that calls setProperty and this is whats displayed in the Application Output:

        itr->first "db" 
    itr->second "{\"db\":\"test\",\"host\":\"localhost\",\"usr\":\"root\",\"pass\":\"resuocra\"}"

    The syntax error is coming from the JSON, but why there is nothing wrong with it. I dumped result.toString() to the console and it contains:

        SyntaxError: Expected token `,'

    The script:

        function test() {
    	try{
    		console.info("---------------");
    		console.info("test(), Line 4");
    
    		if ( db === undefined ) {
    			console.info("db is undefined");
    			return;
    		}
    		if ( typeof db === "object" ) {
    			var mbr;
    			console.info("test(), Line 7");
    			console.info(db);
    			console.info("test(), Line 9");
    			
    			for( mbr in db ) {
    				console.info("test(), Line12");
    				console.info(mbr);
    				console.info("test(), Line14");
    			}
    			console.info("test(), Line 14");			
    		}
    		console.info("test(), Line 16");		
    		console.info("---------------");
    	} catch( e ) {
    		console.warn( "test() WARNING: " + e );
    	}
    }

    When run my application and the script is evaluated I see the following in the "Application Output"

        2020-04-08 08:21:36.320693+0100 XMLMPAM[3657:59571] [js] ---------------
    2020-04-08 08:21:36.320732+0100 XMLMPAM[3657:59571] [js] test(), Line 4
    2020-04-08 08:21:36.320747+0100 XMLMPAM[3657:59571] [js] test(), Line 7
    2020-04-08 08:21:36.320762+0100 XMLMPAM[3657:59571] [js] SyntaxError: Expected token `,'
    2020-04-08 08:21:36.320769+0100 XMLMPAM[3657:59571] [js] test(), Line 9
    2020-04-08 08:21:36.320790+0100 XMLMPAM[3657:59571] [js] test(), Line 14
    2020-04-08 08:21:36.320798+0100 XMLMPAM[3657:59571] [js] test(), Line 16
    2020-04-08 08:21:36.320804+0100 XMLMPAM[3657:59571] [js] ---------------

    Ignore everything before the [js] thats my time stamp and debug information, after the [js] is all the console output.

    What is the:

        SyntaxError: Expected token `,'

    I can see nothing wrong in the global or the script.

    If I modify the script and insert:

        var db =  {"db":"test","host":"localhost","usr":"root","pass":"123456"};

    As the first line, the syntax error is not displayed and everything is ok, so what is wrong with global added using setProperty ?

    Here is the code that adds a global to the map:

        void clsXMLnode::addGlobal(QString strGlobal) {
        QStringList slstGlobal = strGlobal.split(clsXMLnode::msccGlobalDelimiter);

        if ( slstGlobal.length() == clsXMLnode::mscintAssignmentParts ) {
            QString strName(slstGlobal[clsXMLnode::mscintGlobalName].trimmed())
           ,strValue(slstGlobal[clsXMLnode::mscintGlobalValue].trimmed());
            msmpGlobals.insert(std::make_pair(strName, strValue));
        }
    }

    Some definitions:

        clsXMLnode::msccGlobalDelimiter        is "="
    clsXMLnode::mscintAssignmentParts      is 2
    clsXMLnode::mscintGlobalName           is 0
    clsXMLnode::mscintGlobalValue          is 1
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  • The solution was to wrap the JSON in (), this was not required in earlier versions and I fail to see why its required now, but it has solved the issue.

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  • The solution was to wrap the JSON in (), this was not required in earlier versions and I fail to see why its required now, but it has solved the issue.

    0

  • @SPlatten said in QJSEngine and SyntaxError ?:

    The solution was to wrap the JSON in ()

    Where are you doing this? On the c++ side or the qml side? I seem to remember some weirdness with something like this, but I honestly don't remember where the problem was.

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  • In the C++, I'm not using QML in my application.

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  • @fcarney, can you help with this problem? https://forum.qt.io/topic/113478/qjsengine-error-2-problem-after-qt-update/2

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