lib: use private field in AbortController

Instead of validating the receiver ourselves, let V8 handle
the validation using the semantics of private fields.

PR-URL: nodejs#43820
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/internal/abort_controller.js

@@ -292,34 +292,21 @@ function abortSignal(signal, reason) {
   signal.dispatchEvent(event);
 }
 
-// TODO(joyeecheung): use private fields and we'll get invalid access
-// validation from V8 instead of throwing ERR_INVALID_THIS ourselves.
-const kSignal = Symbol('signal');
-
-function validateAbortController(obj) {
-  if (obj?.[kSignal] === undefined)
-    throw new ERR_INVALID_THIS('AbortController');
-}
-
 class AbortController {
-  constructor() {
-    this[kSignal] = createAbortSignal();
-  }
+  #signal = createAbortSignal();
 
   /**
    * @type {AbortSignal}
    */
   get signal() {
-    validateAbortController(this);
-    return this[kSignal];
+    return this.#signal;
   }
 
   /**
    * @param {any} reason
    */
   abort(reason = new DOMException('This operation was aborted', 'AbortError')) {
-    validateAbortController(this);
-    abortSignal(this[kSignal], reason);
+    abortSignal(this.#signal, reason);
   }
 
   [customInspectSymbol](depth, options) {

test/parallel/test-abortcontroller.js

@@ -108,11 +108,11 @@ const { setTimeout: sleep } = require('timers/promises');
   for (const badController of badAbortControllers) {
     throws(
       () => acSignalGet.call(badController),
-      { code: 'ERR_INVALID_THIS', name: 'TypeError' }
+      { name: 'TypeError' }
     );
     throws(
       () => acAbort.call(badController),
-      { code: 'ERR_INVALID_THIS', name: 'TypeError' }
+      { name: 'TypeError' }
     );
   }
 }
@@ -139,7 +139,7 @@ const { setTimeout: sleep } = require('timers/promises');
   for (const badSignal of badAbortSignals) {
     throws(
       () => signalAbortedGet.call(badSignal),
-      { code: 'ERR_INVALID_THIS', name: 'TypeError' }
+      { name: 'TypeError' }
     );
   }
 }