ESM support

[giltayar]

ESM support for testdouble.js, using quibble

[giltayar]

Note that it's almost done, but not quite. Currently, to use ESM, you need to node --loader=quibble, but it doesn't make sense to use quibble. It should be node --loader=testdouble. I'll work on that (nothing major, just some glue code, and an "example" test that checks that it all hangs together), but in the meantime, @searls, if you want, you can review the code.

[searls]

I'm pretty tied up this week, so I'll wait for the all-clear that it's "ready-ready" and then do one big review/fixup en masse if that's ok

[giltayar]

Based on experience, I want to add one more thing: if you didn't specify the loader (node --loader=testdouble) then we should throw an exception to show you that you didn't and not fail silently with unexpected results. For this, I need to change quibble, and then come back here and do a small change.

And then I'm done. Promise! ☺️

[searls]

I shall await your changes!

[giltayar]

@searls And... we're done! Take your time.

I'll start writing that blog post... :-)

[searls]

Mind setting a todo for yourself a few months from now to come back and revisit this?

[searls]

Apologies that github is confused about the merge status, but this is merged! And released! Landed in 3.15.0

Great job seeing this through @giltayar!