lib: add abortSignal.throwIfAborted()

Refs: whatwg/dom#1034 Signed-off-by: James M Snell <[email protected]> PR-URL: #40951 Reviewed-By: Benjamin Gruenbaum <[email protected]>

Author: jasnell

doc/api/globals.md

@@ -179,6 +179,14 @@ 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

lib/internal/abort_controller.js

@@ -141,6 +141,12 @@ class AbortSignal extends EventTarget{
 returnthis[kReason];
 }
 
+throwIfAborted(){
+if(this.aborted){
+throwthis.reason;
+}
+}
+
 [customInspectSymbol](depth,options){
 returncustomInspect(this,{
 aborted: this.aborted
@@ -151,7 +157,8 @@ class AbortSignal extends EventTarget{
  * @param{any} reason
  * @returns{AbortSignal}
  */
-staticabort(reason){
+staticabort(
+reason=newDOMException('This operation was aborted','AbortError')){
 returncreateAbortSignal(true,reason);
 }
 
@@ -311,7 +318,7 @@ class AbortController{
 /**
  * @param{any} reason
  */
-abort(reason){
+abort(reason=newDOMException('This operation was aborted','AbortError')){
 validateAbortController(this);
 abortSignal(this[kSignal],reason);
 }

test/parallel/test-abortcontroller.js

@@ -14,6 +14,8 @@ const{
 const{
  kWeakHandler,
 }=require('internal/event_target');
+const{ internalBinding }=require('internal/test/binding');
+const{ DOMException }=internalBinding('messaging');
 
 const{setTimeout: sleep}=require('timers/promises');
 
@@ -230,3 +232,24 @@ const{setTimeout: sleep } = require('timers/promises');
 // keep the Node.js process open (the timer is unref'd)
 AbortSignal.timeout(1_200_000);
 }
+
+{
+// Test AbortSignal.reason default
+constsignal=AbortSignal.abort();
+ok(signal.reasoninstanceofDOMException);
+strictEqual(signal.reason.code,20);
+
+constac=newAbortController();
+ac.abort();
+ok(ac.signal.reasoninstanceofDOMException);
+strictEqual(ac.signal.reason.code,20);
+}
+
+{
+// Test abortSignal.throwIfAborted()
+throws(()=>AbortSignal.abort().throwIfAborted(),{code: 20});
+
+// Does not throw because it's not aborted.
+constac=newAbortController();
+ac.signal.throwIfAborted();
+}