It's definitely cryptic but stuff like this always happens in dynamic languages. They couldn't have created a process.thisIsNodeJS_NoForRealItIs because anything could fake it. My making it part of the toString it can't be overwritten.
Who cares if it's being "faked", though? The code should just check directly for the existence of process.nextTick, not use a bunch of obfuscatory nonsense to check that the string representation of some object matches some arbitrary string from which you might be able to conclude that you're running on node, from which you can then conclude that you might have access to process.nextTick.
Because Node doesn't own process.nextTick. It's valid for a library to create one in the browser. If I'm writing JS that can be run in Node or the browser I want to know if it's REALLY IS Node or not.
