Adds the listener function to the beginning of the listeners array for the
event named eventName. No checks are made to see if the listener has
already been added. Multiple calls passing the same combination of eventName
and listener will result in the listener being added, and called, multiple times.
Adds the
listener
function to the beginning of the listeners array for the event namedeventName
. No checks are made to see if thelistener
has already been added. Multiple calls passing the same combination ofeventName
andlistener
will result in thelistener
being added, and called, multiple times.Returns a reference to the
EventEmitter
, so that calls can be chained.