Merge pull request #105 from MattiasBuelens/rewrite-transform-stream

Rewrite TransformStream using the public API

etc/web-streams-polyfill.api.md

@@ -10,6 +10,7 @@
 export interface AbortSignal {
     readonly aborted: boolean;
     addEventListener(type: 'abort', listener: () => void): void;
+    readonly reason?: any;
     removeEventListener(type: 'abort', listener: () => void): void;
 }
 

package.json

@@ -90,6 +90,7 @@
     "@typescript-eslint/eslint-plugin": "^4.29.3",
     "@typescript-eslint/parser": "^4.29.3",
     "@ungap/promise-all-settled": "^1.1.2",
+    "abort-controller": "^3.0.0",
     "eslint": "^7.32.0",
     "jasmine": "^3.9.0",
     "micromatch": "^4.0.4",

src/lib/abort-signal.ts

@@ -15,6 +15,11 @@ export interface AbortSignal {
    */
   readonly aborted: boolean;
 
+  /**
+   * The abort reason.
+   */
+  readonly reason?: any;
+
   /**
    * Add an event listener to be triggered when this signal becomes aborted.
    */
@@ -51,7 +56,7 @@ export function isAbortSignal(value: unknown): value is AbortSignal {
 export interface AbortController {
   readonly signal: AbortSignal;
 
-  abort(): void;
+  abort(reason?: any): void;
 }
 
 interface AbortControllerConstructor {

src/lib/readable-stream/default-controller.ts

@@ -307,23 +307,13 @@ export function ReadableStreamDefaultControllerGetDesiredSize(
 export function ReadableStreamDefaultControllerHasBackpressure(
   controller: ReadableStreamDefaultController<any>
 ): boolean {
-  if (ReadableStreamDefaultControllerShouldCallPull(controller)) {
-    return false;
-  }
-
-  return true;
+  return !ReadableStreamDefaultControllerShouldCallPull(controller);
 }
 
 export function ReadableStreamDefaultControllerCanCloseOrEnqueue(
   controller: ReadableStreamDefaultController<any>
 ): boolean {
-  const state = controller._controlledReadableStream._state;
-
-  if (!controller._closeRequested && state === 'readable') {
-    return true;
-  }
-
-  return false;
+  return !controller._closeRequested && controller._controlledReadableStream._state === 'readable';
 }
 
 export function SetUpReadableStreamDefaultController<R>(stream: ReadableStream<R>,