On 8 April 2015 at 22:10, Joerg Bornemann <joerg.bornem...@theqtcompany.com> wrote: > On 08-Apr-15 16:06, Sze Howe Koh wrote: > >> I think we should document this somewhere, if it isn't already done (I >> searched but couldn't find anything). I'm happy to volunteer if >> necessary. Could you please provide a list of built-in properties of >> various QJSValue types? > > > The docs state mention that isError() returns true if the value is an object > of the Error class. That's a JavaScript class. We shouldn't duplicate the > JavaScript documentation.
There are two issues here: 1. The "lineNumber" and "fileName" properties are non-standard. They are Mozilla extensions (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error ), so even some JavaScript devs might not know they exist. 2. The reader might not make the connection, "This is a JavaScript Error object, therefore it has properties that help me debug" -- especially if they don't have a JavaScript background (which I presume is true for a significant number of Qt users). Personally, I scoured the QJSValue page looking for debugging hints, and the only thing that jumped out at me was QJSValue::toString(). May I suggest adding a bit of documentation on our side to help people discover the features? Currently, http://doc.qt.io/qt-5/qjsengine.html#script-exceptions only recommends using toString() to probe errors. That's an ideal place to add a list of standard and non-standard properties that users can take advantage of. >> Also, what do you think of some API that returns a list of available >> properties? (similar to QObject::dynamicPropertyNames() ) > > > See QJSValueIterator. Got it, thanks. Going off on a slight tangent: https://doc.qt.io/qt-5/qjsvalue.html#toVariant says that an Object "is converted to a QVariantMap. Each property is converted to a QVariant, recursively". However, calling toVariant() on an Error object (isError() == isObject() == true) produces an empty QVariantMap event though QJSValueIterator gets the properties just fine (using Qt 5.4.1). Is this expected? Regards, Sze-Howe _______________________________________________ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development
