feat: AbortController polyfill (#9333)

packages/core/abortcontroller/abortsignal.ts

@@ -0,0 +1,80 @@
+
+import { Observable } from '../data/observable';
+
+// Known Limitation
+//   Use `any` because the type of `AbortSignal` in `lib.dom.d.ts` is wrong and
+//   to make assignable our `AbortSignal` into that.
+//   https://github.com/Microsoft/TSJS-lib-generator/pull/623
+type Events = {
+    abort: any // Event & Type<"abort">
+}
+type EventAttributes = {
+    onabort: any // Event & Type<"abort">
+}
+
+/**
+ * The signal class.
+ * @see https://dom.spec.whatwg.org/#abortsignal
+ */
+export default class AbortSignal extends Observable {
+    /**
+     * AbortSignal cannot be constructed directly.
+     */
+    public constructor() {
+        super()
+    }
+
+    /**
+     * Returns `true` if this `AbortSignal`'s `AbortController` has signaled to abort, and `false` otherwise.
+     */
+    public get aborted(): boolean {
+        const aborted = abortedFlags.get(this)
+        if (typeof aborted !== "boolean") {
+            throw new TypeError(
+                `Expected 'this' to be an 'AbortSignal' object, but got ${
+                    this === null ? "null" : typeof this
+                }`,
+            )
+        }
+        return aborted
+    }
+}
+
+/**
+ * Create an AbortSignal object.
+ */
+export function createAbortSignal(): AbortSignal {
+    const signal = new AbortSignal();
+    abortedFlags.set(signal, false)
+    return signal
+}
+
+/**
+ * Abort a given signal.
+ */
+export function abortSignal(signal: AbortSignal): void {
+    if (abortedFlags.get(signal) !== false) {
+        return
+    }
+
+    abortedFlags.set(signal, true)
+    signal.notify({ eventName: "abort", type: "abort" })
+}
+
+/**
+ * Aborted flag for each instances.
+ */
+const abortedFlags = new WeakMap<AbortSignal, boolean>()
+
+// Properties should be enumerable.
+Object.defineProperties(AbortSignal.prototype, {
+    aborted: { enumerable: true },
+})
+
+// `toString()` should return `"[object AbortSignal]"`
+if (typeof Symbol === "function" && typeof Symbol.toStringTag === "symbol") {
+    Object.defineProperty(AbortSignal.prototype, Symbol.toStringTag, {
+        configurable: true,
+        value: "AbortSignal",
+    })
+}

packages/core/abortcontroller/index.ts

@@ -0,0 +1,62 @@
+import AbortSignal, { abortSignal, createAbortSignal } from "./abortsignal"
+/**
+ * The AbortController.
+ * @see https://dom.spec.whatwg.org/#abortcontroller
+ */
+export default class AbortController {
+    /**
+     * Initialize this controller.
+     */
+    public constructor() {
+        signals.set(this, createAbortSignal())
+    }
+
+    /**
+     * Returns the `AbortSignal` object associated with this object.
+     */
+    public get signal(): AbortSignal {
+        return getSignal(this)
+    }
+
+    /**
+     * Abort and signal to any observers that the associated activity is to be aborted.
+     */
+    public abort(): void {
+        abortSignal(getSignal(this))
+    }
+}
+
+/**
+ * Associated signals.
+ */
+const signals = new WeakMap<AbortController, AbortSignal>()
+
+/**
+ * Get the associated signal of a given controller.
+ */
+function getSignal(controller: AbortController): AbortSignal {
+    const signal = signals.get(controller)
+    if (signal == null) {
+        throw new TypeError(
+            `Expected 'this' to be an 'AbortController' object, but got ${
+                controller === null ? "null" : typeof controller
+            }`,
+        )
+    }
+    return signal
+}
+
+// Properties should be enumerable.
+Object.defineProperties(AbortController.prototype, {
+    signal: { enumerable: true },
+    abort: { enumerable: true },
+})
+
+if (typeof Symbol === "function" && typeof Symbol.toStringTag === "symbol") {
+    Object.defineProperty(AbortController.prototype, Symbol.toStringTag, {
+        configurable: true,
+        value: "AbortController",
+    })
+}
+
+export { AbortController, AbortSignal }

packages/core/globals/index.ts

@@ -319,6 +319,9 @@ export function initGlobal() {
 		global.registerModule('fetch', () => require('../fetch'));
 		installPolyfills('fetch', ['fetch', 'Headers', 'Request', 'Response']);
 
+		global.registerModule('abortcontroller', () => require('../abortcontroller'));
+		installPolyfills('abortcontroller', ['AbortController', 'AbortSignal']);
+
 		// Custom decorators
 
 		global.Deprecated = function (target: Object, key?: string | symbol, descriptor?: any) {