lib: add aborted() utility function

Fixes: #37220
Refs: #36607
PR-URL: #46494
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Antoine du Hamel <[email protected]>

doc/api/util.md

@@ -1977,6 +1977,51 @@ const channel = new MessageChannel();
 channel.port2.postMessage(signal, [signal]);
 ```
 
+## `util.aborted(signal, resource)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+> Stability: 1 - Experimental
+
+* `signal` {AbortSignal}
+* `resource` {Object} Any non-null entity, reference to which is held weakly.
+* Returns: {Promise}
+
+Listens to abort event on the provided `signal` and
+returns a promise that is fulfilled when the `signal` is
+aborted. If the passed `resource` is garbage collected before the `signal` is
+aborted, the returned promise shall remain pending indefinitely.
+
+```cjs
+const { aborted } = require('node:util');
+
+const dependent = obtainSomethingAbortable();
+
+aborted(dependent.signal, dependent).then(() => {
+  // Do something when dependent is aborted.
+});
+
+dependent.on('event', () => {
+  dependent.abort();
+});
+```
+
+```mjs
+import { aborted } from 'node:util';
+
+const dependent = obtainSomethingAbortable();
+
+aborted(dependent.signal, dependent).then(() => {
+  // Do something when dependent is aborted.
+});
+
+dependent.on('event', () => {
+  dependent.abort();
+});
+```
+
 ## `util.types`
 
 <!-- YAML

lib/internal/abort_controller.js

@@ -8,6 +8,7 @@ const {
   ObjectDefineProperties,
   ObjectSetPrototypeOf,
   ObjectDefineProperty,
+  PromiseResolve,
   SafeFinalizationRegistry,
   SafeSet,
   Symbol,
@@ -22,11 +23,13 @@ const {
   kTrustEvent,
   kNewListener,
   kRemoveListener,
+  kWeakHandler,
 } = require('internal/event_target');
 const {
+  createDeferredPromise,
   customInspectSymbol,
-  kEnumerableProperty,
   kEmptyObject,
+  kEnumerableProperty,
 } = require('internal/util');
 const { inspect } = require('internal/util/inspect');
 const {
@@ -38,6 +41,8 @@ const {
 } = require('internal/errors');
 
 const {
+  validateAbortSignal,
+  validateObject,
   validateUint32,
 } = require('internal/validators');
 
@@ -94,7 +99,7 @@ function customInspect(self, obj, depth, options) {
   return `${self.constructor.name} ${inspect(obj, opts)}`;
 }
 
-function validateAbortSignal(obj) {
+function validateThisAbortSignal(obj) {
   if (obj?.[kAborted] === undefined)
     throw new ERR_INVALID_THIS('AbortSignal');
 }
@@ -132,15 +137,15 @@ class AbortSignal extends EventTarget {
    * @type {boolean}
    */
   get aborted() {
-    validateAbortSignal(this);
+    validateThisAbortSignal(this);
     return !!this[kAborted];
   }
 
   /**
    * @type {any}
    */
   get reason() {
-    validateAbortSignal(this);
+    validateThisAbortSignal(this);
     return this[kReason];
   }
 
@@ -202,7 +207,7 @@ class AbortSignal extends EventTarget {
   }
 
   [kTransfer]() {
-    validateAbortSignal(this);
+    validateThisAbortSignal(this);
     const aborted = this.aborted;
     if (aborted) {
       const reason = this.reason;
@@ -369,6 +374,24 @@ function transferableAbortController() {
   return AbortController[kMakeTransferable]();
 }
 
+/**
+ * @param {AbortSignal} signal
+ * @param {any} resource
+ * @returns {Promise<void>}
+ */
+async function aborted(signal, resource) {
+  if (signal === undefined) {
+    throw new ERR_INVALID_ARG_TYPE('signal', 'AbortSignal', signal);
+  }
+  validateAbortSignal(signal, 'signal');
+  validateObject(resource, 'resource', { nullable: false, allowFunction: true, allowArray: true });
+  if (signal.aborted)
+    return PromiseResolve();
+  const abortPromise = createDeferredPromise();
+  signal.addEventListener('abort', abortPromise.resolve, { [kWeakHandler]: resource, once: true });
+  return abortPromise.promise;
+}
+
 ObjectDefineProperties(AbortController.prototype, {
   signal: kEnumerableProperty,
   abort: kEnumerableProperty,
@@ -387,6 +410,7 @@ module.exports = {
   AbortController,
   AbortSignal,
   ClonedAbortSignal,
+  aborted,
   transferableAbortSignal,
   transferableAbortController,
 };

lib/util.js

@@ -400,5 +400,8 @@ module.exports = {
   get transferableAbortController() {
     return lazyAbortController().transferableAbortController;
   },
+  get aborted() {
+    return lazyAbortController().aborted;
+  },
   types
 };

test/parallel/test-aborted-util.js

@@ -0,0 +1,59 @@
+// Flags: --expose-gc
+'use strict';
+
+const common = require('../common');
+const { aborted } = require('util');
+const assert = require('assert');
+const { getEventListeners } = require('events');
+const { spawn } = require('child_process');
+
+{
+  // Test aborted works when provided a resource
+  const ac = new AbortController();
+  aborted(ac.signal, {}).then(common.mustCall());
+  ac.abort();
+  assert.strictEqual(ac.signal.aborted, true);
+  assert.strictEqual(getEventListeners(ac.signal, 'abort').length, 0);
+}
+
+{
+  // Test aborted with gc cleanup
+  const ac = new AbortController();
+  aborted(ac.signal, {}).then(common.mustNotCall());
+  setImmediate(() => {
+    global.gc();
+    ac.abort();
+    assert.strictEqual(ac.signal.aborted, true);
+    assert.strictEqual(getEventListeners(ac.signal, 'abort').length, 0);
+  });
+}
+
+{
+  // Fails with error if not provided abort signal
+  Promise.all([{}, null, undefined, Symbol(), [], 1, 0, 1n, true, false, 'a', () => {}].map((sig) =>
+    assert.rejects(aborted(sig, {}), {
+      code: 'ERR_INVALID_ARG_TYPE',
+    })
+  )).then(common.mustCall());
+}
+
+{
+  // Fails if not provided a resource
+  const ac = new AbortController();
+  Promise.all([null, undefined, 0, 1, 0n, 1n, Symbol(), '', 'a'].map((resource) =>
+    assert.rejects(aborted(ac.signal, resource), {
+      code: 'ERR_INVALID_ARG_TYPE',
+    })
+  )).then(common.mustCall());
+}
+
+{
+  const childProcess = spawn(process.execPath, ['--input-type=module']);
+  childProcess.on('exit', common.mustCall((code) => {
+    assert.strictEqual(code, 13);
+  }));
+  childProcess.stdin.end(`
+    import { aborted } from 'node:util';
+    await aborted(new AbortController().signal, {});
+  `);
+}