AsyncResource

open external class AsyncResource(source)

The class AsyncResource is designed to be extended by the embedder's async resources. Using this, users can easily trigger the lifetime events of their own resources.

The init hook will trigger when an AsyncResource is instantiated.

The following is an overview of the AsyncResource API.

import { AsyncResource, executionAsyncId } from 'node:async_hooks';

// AsyncResource() is meant to be extended. Instantiating a
// new AsyncResource() also triggers init. If triggerAsyncId is omitted then
// async_hook.executionAsyncId() is used.
const asyncResource = new AsyncResource(
type, { triggerAsyncId: executionAsyncId(), requireManualDestroy: false },
);

// Run a function in the execution context of the resource. This will
// * establish the context of the resource
// * trigger the AsyncHooks before callbacks
// * call the provided function `fn` with the supplied arguments
// * trigger the AsyncHooks after callbacks
// * restore the original execution context
asyncResource.runInAsyncScope(fn, thisArg, ...args);

// Call AsyncHooks destroy callbacks.
asyncResource.emitDestroy();

// Return the unique ID assigned to the AsyncResource instance.
asyncResource.asyncId();

// Return the trigger ID for the AsyncResource instance.
asyncResource.triggerAsyncId();

Inheritors

Constructors

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constructor(type: String)

AsyncResource() is meant to be extended. Instantiating a new AsyncResource() also triggers init. If triggerAsyncId is omitted then async_hook.executionAsyncId() is used.

constructor(type: String, triggerAsyncId: Double = definedExternally)

AsyncResource() is meant to be extended. Instantiating a new AsyncResource() also triggers init. If triggerAsyncId is omitted then async_hook.executionAsyncId() is used.

constructor(type: String, triggerAsyncId: AsyncResourceOptions = definedExternally)

AsyncResource() is meant to be extended. Instantiating a new AsyncResource() also triggers init. If triggerAsyncId is omitted then async_hook.executionAsyncId() is used.

Types

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object Companion

Functions

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fun <Func : Function<Any?>> bind(fn: Func): Func

Binds the given function to execute to this AsyncResource's scope.

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Call all destroy hooks. This should only ever be called once. An error will be thrown if it is called more than once. This must be manually called. If the resource is left to be collected by the GC then the destroy hooks will never be called.

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fun <This, Result> runInAsyncScope(fn: Function<Result>, thisArg: This = definedExternally, vararg args: Any?): Result

Call the provided function with the provided arguments in the execution context of the async resource. This will establish the context, trigger the AsyncHooks before callbacks, call the function, trigger the AsyncHooks after callbacks, and then restore the original execution context.

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