Implement AbortSignal.timeout

Author: mrbbot

packages/core/src/plugins/core.ts

@@ -36,6 +36,7 @@ import {
 import { File, FormData, Headers } from "undici";
 import { MiniflareCoreError } from "../error";
 import {
+  AbortSignal,
   DOMException,
   FetchEvent,
   Request,
@@ -366,11 +367,7 @@ export class CorePlugin extends Plugin<CoreOptions> implements CoreOptions {
       Event,
       EventTarget,
       AbortController,
-      // Fix for Jest :(, jest-environment-node doesn't include AbortSignal in
-      // the global scope, but does include AbortController
-      AbortSignal:
-        globalThis.AbortSignal ??
-        Object.getPrototypeOf(new AbortController().signal).constructor,
+      AbortSignal,
 
       FetchEvent,
       ScheduledEvent,

packages/core/src/standards/timers.ts

@@ -29,3 +29,23 @@ export function inputGatedSetInterval<Args extends any[]>(
     ...args
   );
 }
+
+// Fix for Jest :(, jest-environment-node doesn't include AbortSignal in
+// the global scope, but does include AbortController
+export const AbortSignal =
+  globalThis.AbortSignal ??
+  Object.getPrototypeOf(new AbortController().signal).constructor;
+
+// Polyfill `AbortSignal.timeout` as described here:
+// https://community.cloudflare.com/t/2021-12-10-workers-runtime-release-notes/334982
+// @ts-expect-error `timeout` isn't included in Node.js yet
+AbortSignal.timeout ??= (ms?: number) => {
+  if (typeof ms !== "number") {
+    throw new TypeError(
+      "Failed to execute 'timeout' on 'AbortSignal': parameter 1 is not of type 'integer'."
+    );
+  }
+  const controller = new AbortController();
+  setTimeout(() => controller.abort(), ms);
+  return controller.signal;
+};

packages/core/test/standards/timers.spec.ts

@@ -5,7 +5,7 @@ import {
   triggerPromise,
   waitsForInputGate,
 } from "@miniflare/shared-test";
-import test from "ava";
+import test, { ThrowsExpectation } from "ava";
 
 test("inputGatedSetTimeout: calls callback with no input gate in context", async (t) => {
   const [trigger, promise] = triggerPromise<[number, string]>();
@@ -92,3 +92,31 @@ test("inputGatedSetInterval: waits for input gate to open before calling callbac
 
   clearInterval(handle);
 });
+
+test("AbortSignal.timeout: triggers signal after timeout", async (t) => {
+  // @ts-expect-error `timeout` isn't included in Node.js yet
+  const signal = AbortSignal.timeout(50);
+  let aborted;
+  signal.addEventListener("abort", () => (aborted = true));
+  t.false(signal.aborted);
+  await setTimeout(100);
+  t.true(signal.aborted);
+  t.true(aborted);
+});
+test("AbortSignal.timeout: requires numeric timeout", (t) => {
+  const expectations: ThrowsExpectation = {
+    instanceOf: TypeError,
+    message:
+      "Failed to execute 'timeout' on 'AbortSignal': parameter 1 is not of type 'integer'.",
+  };
+  // @ts-expect-error `timeout` isn't included in Node.js yet
+  t.throws(() => AbortSignal.timeout(), expectations);
+  // @ts-expect-error `timeout` isn't included in Node.js yet
+  t.throws(() => AbortSignal.timeout("42"), expectations);
+});
+test("AbortSignal.timeout: included on constructor obtained via AbortController#signal prototype", (t) => {
+  const controller = new AbortController();
+  const constructor = Object.getPrototypeOf(controller.signal).constructor;
+  // @ts-expect-error `timeout` isn't included in Node.js yet
+  t.is(constructor.timeout, AbortSignal.timeout);
+});