Function new_handle 

pub fn new_handle(id: u64, tag: &'static str) -> Value

Build the handle object a set* call returns: an @@native-tagged object ("Timeout" or "Immediate") carrying the scheduler’s timer id in a hidden @@timerId slot.

Node’s handles coerce to their integer id (String(t) is "2"), which is what keeps clearTimeout working for code that stashed the return value in a number. valueOf/toString reproduce that for both ToPrimitive hints — Node reaches it via an own Symbol.toPrimitive, which this does not model.