There is now some better documentation about building with a VM at https://github.com/espruino/Espruino#building-under-windowsmacos-with-a-vm
However @DrAzzy's Amazon EC2 Instance may still be easier if you don't want to do any big downloads.
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
There is now some better documentation about building with a VM at https://github.com/espruino/Espruino#building-under-windowsmacos-with-a-vm
However @DrAzzy's Amazon EC2 Instance may still be easier if you don't want to do any big downloads.