Developing server software in JS was becoming a thing & I was part of this shift. Given that I was writing desktop application in JS for TomTom in XULRunner it was obvious to me that we would want to use the same code to write cross platform desktop application as well. So I have worked on a predecessor of ElectorJS it was both fun & challenging to implement and expose API compatible with a rest of the ecosystem through XPCOM bindings.
This work was eventually got recognized by some at Mozilla where I then was hired to work on Firefox Extensions, they were also was interested in interop with growing server JS ecosystem.