gnome-shell has  a nice integrated developer tool called “Looking glass”. To bring it up, simply enter “lg” into the command prompt:

Alt-F2 lg

This brings up a translucent overlay with an interactive JavaScript prompt. Among the nice things it offers are tab completion and an object picker.

Here is how it looks:

If you haven’t tried it yet,  you really should.

Over the years, many people have asked,

“Can I use Looking glass to debug my GTK+ application ?”.

So far, the answer has always been no. But now, the always awesome Alex Larsson has stepped up and made essentially the same functionality available for the GTK+ Inspector:

As you can see, it has an object picker, tab completion and a result history just like its ‘big brother’.  Alex made a little demo video for it.

To avoid a gjs dependency in GTK+ itself and the associated cyclic dependency issues, this is implemented as an extension in a loadable module.  The code currently lives on github, in Alex’ gjs-inspector repository.

Enjoy