window.openFileDialog()'s list has objects with no properties

[cookiengineer]

When using the window.openFileDialog() API, the returned list that the callback receives as a parameter is an empty object with no keys and no values.

window.openFileDialog([
    'png', 'json'
], function(result) {

    for (let r = 0, rl = result.length; r < rl; r++) {
        let entry = result[r];
        console.log(typeof entry, JSON.stringify(Object.keys(entry));
        console.log(typeof entry, JSON.stringify(Object.values(entry));
    }

});

Both Object.keys() and Object.values() return empty Arrays. When stringifying the entries themselves, they are just empty objects ({}). I was trying to figure out myself what was going on inside the X11UIInterface.cpp/h files, but to be honest I have no clue how the memory looks like and how to properly convert/verify the data there.

Tested system: Up-to-date archlinux, with GNOME3 stable.

[efyx]

The issue is not related to window.openFileDialog(), as it does return an array of File object as expected.

The problem is that Object.keys([File Object]) return an empty array despite the fact the the filesize and filename property are listed as enumerable properties ( See https://github.com/nidium/Nidium/blob/master/src/Binding/JSFile.cpp#L794-L798 and https://github.com/nidium/Nidium/blob/master/src/Binding/ClassMapper.h#L36-L43 )

The documentation for Object.keys says that :

The Object.keys() method returns an array of a given object's own enumerable properties, in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).

It turns out that listing the properties with for...in loop work as expected. My guess is that since the properties are defined on the prototype of the File object Object.keys will not return anything defined on the prototype, only instance variable. This behavior seems to be consistent with browsers implementation of File object and other, so I don't think this is an issue.

Pure JS example :

var Demo = function() { this.foo = "foo"; }
Demo.prototype.bar = "bar"
var d = new Demo();
console.log(Object.keys(d)); // Will only list "foo"
console.log(Object.getOwnPropertyNames(d)); // Will list "foo" and "bar" properties

@paraboul any thoughts ?