Module async_hooks 

Node async_hooks module — honest minimal implementation.

There IS a real async-resource id graph, but only over the resources this module itself creates:

• Every new AsyncResource(type) takes the next monotonically increasing asyncId (from 2; Node reserves 1 for the root context) and records the creating context’s id as its triggerAsyncId.
• runInAsyncScope makes that pair the current execution context for the duration of the call, so executionAsyncId() inside reports the resource and a resource constructed there inherits it as its parent. Nesting runInAsyncScope therefore builds a real parent chain.

What is NOT modeled: node-js does not instrument timers, promises, sockets or any other engine-level async resource, so executionAsyncId() inside a setTimeout/.then callback reports the ROOT context (1) rather than a per-callback id, and triggerAsyncId() there reports 0. Only the AsyncResource graph above is real. Consequently:

• createHook({ init, before, after, destroy }) returns a hook object with chainable enable()/disable(). The registered callbacks are stored nowhere and NEVER FIRE — node-js does not instrument async resource lifetimes. This is intentional; do not treat it as a gap to “fill” by faking hook invocations.

What IS real is AsyncLocalStorage for the SYNCHRONOUS case: run(store, cb) makes getStore() return store for the duration of cb (and restores the previous store afterwards), and enterWith(store) sets the current store for subsequent synchronous getStore() calls. Because there is no async-context propagation, a store set with enterWith (or visible inside run) does NOT automatically follow into setTimeout/Promise callbacks — cross-async propagation is not modeled. Within straight-line synchronous code the store is correct.

Instances are @@native-tagged objects (AsyncLocalStorage / AsyncHook) dispatched through instance_call; the parent wires construct, native_tag, instance_has_method, and instance_call (see the report).

Constants

ALS_METHODS

Instance method names by native tag — for the parent’s instance_has_method so a method read (als.run.bind(...)) resolves before it is invoked.

HOOK_METHODS

METHODS

Module-level callable members.

RESOURCE_METHODS

RESOURCE_STATIC_METHODS

Static members on the AsyncResource constructor itself.

Functions

call

construct

Construct a stdlib class instance (new AsyncLocalStorage()). None for any other name so the parent’s construct can fall through.

execution_async_id

The id of the currently-executing async context (Node’s executionAsyncId).

instance_call

Dispatch a method on a native async_hooks instance.

static_call

AsyncResource.bind(fn[, type[, thisArg]]) — with no async-context graph to capture there is nothing to restore, so the bound function IS fn (bound to thisArg when one is given). Node’s own semantics reduce to this whenever no context is active.

trigger_async_id

The id of the context that created the currently-executing one.