Module Atomics

The Atomics object provides atomic operations as static methods. They are used with SharedArrayBuffer objects.

The Atomic operations are installed on an Atomics module. Unlike the other global objects, Atomics is not a constructor. You cannot use it with a new operator or invoke the Atomics object as a function. All properties and methods of Atomics are static (as is the case with the Math object, for example). MDN documentation

Functions

add

The static Atomics.add() method adds a given value at a given position in the array and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

add_bigint

The static Atomics.add() method adds a given value at a given position in the array and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

and

The static Atomics.and() method computes a bitwise AND with a given value at a given position in the array, and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

and_bigint

The static Atomics.and() method computes a bitwise AND with a given value at a given position in the array, and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

compare_exchange

The static Atomics.compareExchange() method exchanges a given replacement value at a given position in the array, if a given expected value equals the old value. It returns the old value at that position whether it was equal to the expected value or not. This atomic operation guarantees that no other write happens until the modified value is written back.

compare_exchange_bigint

The static Atomics.compareExchange() method exchanges a given replacement value at a given position in the array, if a given expected value equals the old value. It returns the old value at that position whether it was equal to the expected value or not. This atomic operation guarantees that no other write happens until the modified value is written back.

exchange

The static Atomics.exchange() method stores a given value at a given position in the array and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

exchange_bigint

The static Atomics.exchange() method stores a given value at a given position in the array and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

is_lock_free

The static Atomics.isLockFree() method is used to determine whether to use locks or atomic operations. It returns true, if the given size is one of the BYTES_PER_ELEMENT property of integer TypedArray types.

load

The static Atomics.load() method returns a value at a given position in the array.

load_bigint

The static Atomics.load() method returns a value at a given position in the array.

notify

The static Atomics.notify() method notifies up some agents that are sleeping in the wait queue. Note: This operation works with a shared Int32Array only. If count is not provided, notifies all the agents in the queue.

notify_with_count

Notifies up to count agents in the wait queue.

or

The static Atomics.or() method computes a bitwise OR with a given value at a given position in the array, and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

or_bigint

The static Atomics.or() method computes a bitwise OR with a given value at a given position in the array, and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

store

The static Atomics.store() method stores a given value at the given position in the array and returns that value.

store_bigint

The static Atomics.store() method stores a given value at the given position in the array and returns that value.

sub

The static Atomics.sub() method subtracts a given value at a given position in the array and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

sub_bigint

The static Atomics.sub() method subtracts a given value at a given position in the array and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

wait

The static Atomics.wait() method verifies that a given position in an Int32Array still contains a given value and if so sleeps, awaiting a wakeup or a timeout. It returns a string which is either “ok”, “not-equal”, or “timed-out”. Note: This operation only works with a shared Int32Array and may not be allowed on the main thread.

wait_async

The static Atomics.waitAsync() method verifies that a given position in an Int32Array still contains a given value and if so sleeps, awaiting a wakeup or a timeout. It returns an object with two properties. The first property async is a boolean which if true indicates that the second property value is a promise. If async is false then value is a string whether equal to either “not-equal” or “timed-out”. Note: This operation only works with a shared Int32Array and may be used on the main thread.

wait_async_bigint

The static Atomics.waitAsync() method verifies that a given position in an Int32Array still contains a given value and if so sleeps, awaiting a wakeup or a timeout. It returns an object with two properties. The first property async is a boolean which if true indicates that the second property value is a promise. If async is false then value is a string whether equal to either “not-equal” or “timed-out”. Note: This operation only works with a shared BigInt64Array and may be used on the main thread.

wait_async_with_timeout

Like waitAsync(), but with timeout

wait_async_with_timeout_bigint

Like waitAsync(), but with timeout

wait_bigint

The static Atomics.wait() method verifies that a given position in an BigInt64Array still contains a given value and if so sleeps, awaiting a wakeup or a timeout. It returns a string which is either “ok”, “not-equal”, or “timed-out”. Note: This operation only works with a shared BigInt64Array and may not be allowed on the main thread.

wait_with_timeout

Like wait(), but with timeout

wait_with_timeout_bigint

Like wait(), but with timeout

xor

The static Atomics.xor() method computes a bitwise XOR with a given value at a given position in the array, and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.

xor_bigint

The static Atomics.xor() method computes a bitwise XOR with a given value at a given position in the array, and returns the old value at that position. This atomic operation guarantees that no other write happens until the modified value is written back.