Does the Espruino support sleep mode?

I am trying toevaluate whether the Espruino is suitable for my project.
I may be asking an obvious question, but I could not find the answer in the documentation.

In the event loop if nothing happens, does the processer enter the sleep mode to conserve power?

Does the javascript interpreter let you go into sleep mode and wake up through a command/ subroutine call?

thank you in advance for any answers.

with kind regards,
peter