Is there a way to launch the firmware on the console?

I know that it is possible to start espruino itself, but then there is no

Bangle.*

Can I get espruino to load the current Bangle/Emscripten build on the console?
I have successfully created emulator_banglejs2.js.
But when I create

./espruino emulator_banglejs2.js

I get the following error:

 ____                 _
|  __|___ ___ ___ _ _|_|___ ___
|  __|_ -| . |  _| | | |   | . |
|____|___|  _|_| |___|_|_|_|___|
         |_| espruino.com
 2v14.49 (c) 2021 G.Williams

Espruino is Open Source. Our work is supported
only by sales of official boards and donations:
http://espruino.com/Donate

Uncaught Error: Can only use 'arguments' variable inside a function

The emulator_banglejs2.js file is an Espruino binary designed to run in the browser, so you can't really run the Espruino binary from an Espruino binary :)

In theory you could build a native Espruino build with some Bangle.js functionality, but the best bet is probably to run emulator_banglejs2.js from Node.js.

There's an example of doing that here:

https://github.com/espruino/BangleApps/blob/master/bin/thumbnailer.js

But there is no REPL implemented - one could possibly be added though, in the same way it's done when emulator_banglejs2.js runs from the Web IDE.