qt - QJSEngine: print to console -

i'm moving qscriptengine (which deprecated) qjsengine, , see i'm unable use print:

  qjsengine engine;    qjsvalue val = engine.evaluate(         "print('123');"         );    if (val.iserror()){      qdebug() << "error: " << val.tostring();   }    qdebug() << "val: " << val.tovariant(); 

the output is:

error:  "referenceerror: print not defined" 

in qscriptengine works.

then, way print console in qjsengine? can't find in docs. tried use console.log, console not defined well.

the print function not implemented in qjsengine. have implement yourself. luckily can write qobjects , make them available in script. (see section "qobject integration" @ http://doc.qt.io/qt-5/qjsengine.html)

here's how i've done it:

create class jsconsole inheriting qobject:

your own console class

jsconsole.h

#ifndef jsconsole_h #define jsconsole_h  #include <qobject>  class jsconsole : public qobject {     q_object public:     explicit jsconsole(qobject *parent = 0);  signals:  public slots:     void log(qstring msg); };  #endif // jsconsole_h 

jsconsole.cpp

#include "jsconsole.h" #include <qdebug>   jsconsole::jsconsole(qobject *parent) :     qobject(parent) { }  void jsconsole::log(qstring msg) {     qdebug() << "jsconsole: "<< msg; } 

using it

now create proxy object in js engine using qjsengine.newqobject. after add global object , use it.

qjsengine engine; jsconsole console; qjsvalue consoleobj =  engine.newqobject(&console); engine.globalobject().setproperty("console", consoleobj); qjsvalue result = engine.evaluate("console.log('test');"); 

error logging

i've searched long time errors in c++ code, when made spelling error in js file. following snippet have helped avoid that.

if (result.iserror()) {     qdebug() << "result: " << result.property("linenumber").toint() << ":" << result.tostring(); } 

ps: first post after years of lurking. i've read tips on writing great answers if i've made mistakes/bad things please tell me.

may code you