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Node.js v4.7.1-test201701051035318070 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 immediateObject
, as created by setImmediate
, from triggering.
clearInterval(intervalObject)#
Stops an intervalObject
, as created by setInterval
, from triggering.
clearTimeout(timeoutObject)#
Prevents a timeoutObject
, as created by setTimeout
, from triggering.
ref()#
If a timer was previously unref()
d, then ref()
can be called 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][, ...])#
Schedules "immediate" execution of callback
after I/O events'
callbacks and before timers set by setTimeout
and setInterval
are
triggered. Returns an immediateObject
for possible use with
clearImmediate
. Additional optional arguments may be passed 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 an immediate is queued from inside an executing callback, that immediate won't fire until the next event loop iteration.
setInterval(callback, delay[, arg][, ...])#
Schedules repeated execution of callback
every delay
milliseconds.
Returns a intervalObject
for possible use with clearInterval
. Additional
optional arguments may be passed 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][, ...])#
Schedules execution of a one-time callback
after delay
milliseconds.
Returns a timeoutObject
for possible use with clearTimeout
. Additional
optional arguments may be passed 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 allows the creation of 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
, unref
creates 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.