Make it possible to give externals names/util.inspect.custom

[emilbayes]

Is your feature request related to a problem? Please describe.

In hyperdivision/hid we use externals as handles for device opaque descriptors, however during debugging it's hard to know what exactly you are working with. I want to preserve the opaqueness of the handles, but it would be nice if I could give these externals a name.

Describe the solution you'd like

Currently externals end up here in util.inspect:

node/lib/internal/util/inspect.js

Line 748 in 2b8b230

return ctx.stylize('[External]', 'special');

I don't know if this should be another API in N-API, the possibility of setting util.inspect.custom or similar.

Describe alternatives you've considered

object_wrap is another alternative, but comes with much more features and boilerplate than I need. I just want to be able to give human readable names to opaque references for debugging.

[bnoordhuis]

I think an override using util.inspect.custom would be acceptable. PR welcome.

[himself65]

I'm working on this now

[addaleax]

I think the only practical solution here would be to print the underlying pointer value if showHidden: true is set. (I would not print the pointer value by default as that may be used in remote code execution attacks.) How does that sound?

[rosaxxny]

Hi, I'd like to work on this.