From 02cc0eeebd5d9cb9edad2ff5f7183f2586c6a3d4 Mon Sep 17 00:00:00 2001
From: James M Snell <jasnell@gmail.com>
Date: Wed, 24 Nov 2021 07:28:30 -0800
Subject: [PATCH] lib: add abortSignal.throwIfAborted()

Refs: https://github.com/whatwg/dom/pull/1034
Signed-off-by: James M Snell <jasnell@gmail.com>
---
 doc/api/globals.md                    |  8 ++++++++
 lib/internal/abort_controller.js      | 15 +++++++++++++--
 test/parallel/test-abortcontroller.js | 17 +++++++++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/doc/api/globals.md b/doc/api/globals.md
index 88e9aad9df21f8..6c8dde7ae10e0a 100644
--- a/doc/api/globals.md
+++ b/doc/api/globals.md
@@ -180,6 +180,14 @@ ac.abort(new Error('boom!'));
 console.log(ac.signal.reason);  // Error('boom!');
 ```
 
+#### `abortSignal.throwIfAborted()`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+If `abortSignal.aborted` is `true`, throws `abortSignal.reason`.
+
 ## Class: `Buffer`
 
 <!-- YAML
diff --git a/lib/internal/abort_controller.js b/lib/internal/abort_controller.js
index 87495ddb7fc381..48df6f3331d16f 100644
--- a/lib/internal/abort_controller.js
+++ b/lib/internal/abort_controller.js
@@ -29,6 +29,10 @@ const {
   }
 } = require('internal/errors');
 
+const {
+  DOMException,
+} = internalBinding('messaging');
+
 const kAborted = Symbol('kAborted');
 const kReason = Symbol('kReason');
 
@@ -69,6 +73,12 @@ class AbortSignal extends EventTarget {
     return this[kReason];
   }
 
+  throwIfAborted() {
+    if (this.aborted) {
+      throw this.reason;
+    }
+  }
+
   [customInspectSymbol](depth, options) {
     return customInspect(this, {
       aborted: this.aborted
@@ -79,7 +89,8 @@ class AbortSignal extends EventTarget {
    * @param {any} reason
    * @returns {AbortSignal}
    */
-  static abort(reason) {
+  static abort(
+      reason = new DOMException('This operation was aborted', 'AbortError')) {
     return createAbortSignal(true, reason);
   }
 }
@@ -141,7 +152,7 @@ class AbortController {
   /**
    * @param {any} reason
    */
-  abort(reason) {
+  abort(reason = new DOMException('This operation was aborted', 'AbortError')) {
     validateAbortController(this);
     abortSignal(this[kSignal], reason);
   }
diff --git a/test/parallel/test-abortcontroller.js b/test/parallel/test-abortcontroller.js
index 0e2cc7d66e7ca0..f60b78509b8eff 100644
--- a/test/parallel/test-abortcontroller.js
+++ b/test/parallel/test-abortcontroller.js
@@ -153,3 +153,20 @@ const { ok, strictEqual, throws } = require('assert');
   const signal = AbortSignal.abort('reason');
   strictEqual(signal.reason, 'reason');
 }
+
+{
+  // Test AbortSignal.reason default
+  const signal = AbortSignal.abort();
+  ok(signal.reason instanceof DOMException);
+  strictEqual(signal.reason.code, 20);
+
+  const ac = new AbortController();
+  ac.abort();
+  ok(ac.signal.reason instanceof DOMException);
+  strictEqual(ac.signal.reason.code, 20);
+}
+
+{
+  // Test abortSignal.throwIfAborted()
+  throws(() => AbortSignal.abort().throwIfAborted(), { code: 20 });
+}