The **task** library allows for functions and threads to be scheduled with the
Task Scheduler.

The functions available in this library generally support functions and
threads. In most cases using a function is sufficient, but for more advanced
cases it's recommended you familiarize yourself with the `Library.coroutine`
library.


Accepts a function or a thread (as returned by coroutine.create) and
calls/resumes it immediately through the engine's scheduler. Arguments
after the first are sent to the function/thread. This function does not
return any value, even if the provided function returns one immediately.

This function is based on the fastSpawn pattern rather than being a
replacement for the deprecated global `spawn` function. It is recommended
that this function be used in place of fastSpawn.


task.spawn

functionOrThread

A function or a thread returned by coroutine.create.


Arguments to send to the function or thread.


Calls/resumes a function/coroutine immediately through the engine
scheduler.


Accepts a function or a thread (as returned by coroutine.create) and
defers it until the next
[resumption cycle](https://devforum.roblox.com/t/1240569), at which point
it is resumed with the engine's scheduler like with
`Library.task.spawn()`. Arguments after the first are sent to the
function/thread. This function does not return any value, even if the
provided function returns one immediately.

This function should be used when a similar behavior to
`Library.task.spawn()` is desirable, but the thread does not need to run
immediately.


task.defer

Calls/resumes a function/coroutine on the next resumption cycle.


Accepts a function or a thread (as returned by coroutine.create) and
schedules it to be called/resumed on the next
`Class.RunService.Heartbeat|Heartbeat` after the given amount of time in
seconds has elapsed. Arguments after the second are sent to the
function/thread.

This function differs from the deprecated global `delay` function in that
**no throttling occurs**: on the very same Heartbeat step in which enough
time has passed, the function is guaranteed to be called/resumed.
Providing a duration of zero (0) will guarantee that the function is
called on the very next Heartbeat.

You can calculate the actual time passed by calling `Library.os.clock()`
upon scheduling and in the scheduled function.


task.delay

duration

The minimum number of seconds that must pass before the
function/thread is called/resumed.


Arguments to be passed to the function/thread when it is due to be
called/resumed.


Schedules a function/coroutine to be called/resumed on the next Heartbeat
after the given duration (in seconds) has passed, without throttling.


Causes the following code to be run in parallel. If the script is already
running in parallel, no change occurs. For more information, see
[Parallel Luau](/scripting/luau/parallel-luau).


task.desynchronize

Causes the following code to be run in parallel.


Causes the following code to be run in serial. If the script is already
running in serial, no change occurs. For more information, see
[Parallel Luau](/scripting/luau/parallel-luau).


task.synchronize

Causes the following code to be run in serial.


Yields the current thread until the given duration (in seconds) has
elapsed, then resumes the thread on the next
`Class.RunService.Heartbeat|Heartbeat` step. The actual amount of time
elapsed is returned.

If no duration is given, it will default to zero (0). This means the
thread resumes on the very next step, which is equivalent in behavior to
`RunService.Heartbeat:Wait()`

Unlike the deprecated global `wait`, this function **does not throttle**
and guarantees the resumption of the thread on the first Heartbeat that
occurs when it is due. This function also only returns the elapsed time
and nothing else.


task.wait

The amount of time in seconds that should elapse before the current
thread is resumed.


Yields the current thread until the next Heartbeat in which the given
duration (in seconds) has passed, without throttling.


Cancels a thread and closes it, preventing it from being resumed manually
or by the task scheduler.

This function can be used with other members of the task library that
return a thread to cancel them before they are resumed. For example:

```lua
local thread = task.delay(5, function ()
  print("Hello world!")
end)

task.cancel(thread)
```

Note: Threads may be in a state where it is impossible to cancel them. For
example, the currently executing thread and threads that have resumed
another coroutine may not be cancelled. If this is the case, a lua error
will be generated.

However, code should not rely on specific thread states or conditions
causing `Library.task.cancel()` to fail. It is possible that future
updates will eliminate these constraints and allow threads in these states
to be successfully cancelled.


task.cancel

thread

Cancels a thread, preventing it from being resumed.


task

Allows for functions and threads to be coordinated with the Task Scheduler.


Default Value: {defaultValueStart}{defaultValueEnd}

This function returns immediately if possible, but can yield the thread that called it until it can return a value.

This member doesn’t appear in the object browser and is not intended for widespread use.

This member is only accessible only through the command bar. Attempting to access this member from scripts causes an error.

This function can’t pause the Lua thread that called it.

Attempting to access this member in scripts causes an error. You might be able to access this member from Roblox Studio's property window.

This member doesn’t appear in Roblox Studio’s Object Browser.

You can’t create an instance of this class with the Instance.new constructor.

Roblox does not replicate this member across its server-client boundary.

Lua code can’t access this member. You might be able to change its value from the property window in Roblox Studio.

This object’s replication behavior is dependent on the player who owns it.

This member is accessible only through the command bar and plugins only. Attempting to access this member from scripts causes an error.

This property is read-only and is safe to read in unsynchronized threads. Attempting to write to it causes an error.

This member is read only. Attempting to write to this member causes an error.

This member is accessible only in CoreScripts.

Only Roblox CoreScripts can access this member, and it isn’t usable by Players.

You can read and write to this property safely from multiple threads.

This class is a top-level singleton. Retrieve an instance of this class with the GetService function.

Multiple threads can potentially write to this property, so it’s unsafe to read from unsynchronized threads.

This function pauses the Lua thread that called it until it returns a result. This doesn’t interrupt other scripts.

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task

Summary

Functions

Functions

spawn

Parameters

Returns

defer

Parameters

Returns

delay

Parameters

Returns

desynchronize

Returns

synchronize

Returns

wait

Parameters

Returns

cancel

Parameters

Returns