Opposite of unref()
. Calling ref()
on a previously unref()
ed port will
not let the program exit if it’s the only active handle left (the default
behavior). If the port is ref()
ed, calling ref()
again will have no effect.
If listeners are attached or removed using .on('message')
, the port will
be ref()
ed and unref()
ed automatically depending on whether
listeners for the event exist.