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Node.js v5.5.0 Documentation
Table of Contents
Timers#
Stability: 3 - Locked
All of the timer functions are globals. You do not need to require()
this module in order to use them.
clearImmediate(immediateObject)#
Stops an immediate from triggering.
clearInterval(intervalObject)#
Stops an interval from triggering.
clearTimeout(timeoutObject)#
Prevents a timeout from triggering.
ref()#
If you had previously unref()
d a timer you can call ref()
to explicitly
request the timer hold the program open. If the timer is already ref
d calling
ref
again will have no effect.
Returns the timer.
setImmediate(callback[, arg][, ...])#
To schedule the "immediate" execution of callback
after I/O events
callbacks and before setTimeout
and setInterval
. Returns an
immediateObject
for possible use with clearImmediate()
. Optionally you
can also pass arguments to the callback.
Callbacks for immediates are queued in the order in which they were created. The entire callback queue is processed every event loop iteration. If you queue an immediate from inside an executing callback, that immediate won't fire until the next event loop iteration.
setInterval(callback, delay[, arg][, ...])#
To schedule the repeated execution of callback
every delay
milliseconds.
Returns a intervalObject
for possible use with clearInterval()
. Optionally
you can also pass arguments to the callback.
To follow browser behavior, when using delays larger than 2147483647
milliseconds (approximately 25 days) or less than 1, Node.js will use 1 as the
delay
.
setTimeout(callback, delay[, arg][, ...])#
To schedule execution of a one-time callback
after delay
milliseconds.
Returns a timeoutObject
for possible use with clearTimeout()
. Optionally you
can also pass arguments to the callback.
The callback will likely not be invoked in precisely delay
milliseconds.
Node.js makes no guarantees about the exact timing of when callbacks will fire,
nor of their ordering. The callback will be called as close as possible to the
time specified.
To follow browser behavior, when using delays larger than 2147483647
milliseconds (approximately 25 days) or less than 1, the timeout is executed
immediately, as if the delay
was set to 1.
unref()#
The opaque value returned by setTimeout
and setInterval
also has the
method timer.unref()
which will allow you to create a timer that is active but
if it is the only item left in the event loop, it won't keep the program
running. If the timer is already unref
d calling unref
again will have no
effect.
In the case of setTimeout
when you unref
you create a separate timer that
will wakeup the event loop, creating too many of these may adversely effect
event loop performance -- use wisely.
Returns the timer.