From f3568c7641df06bad075908805226d1b488b5897 Mon Sep 17 00:00:00 2001
From: Kuba Orlik <kontakt@kuba-orlik.name>
Date: Sat, 27 Mar 2021 22:14:58 +0100
Subject: [PATCH] working deadlyrace

---
 src/index.ts | 128 ++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 105 insertions(+), 23 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 9a0c512..16aec37 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,5 @@
 import Emittery from "emittery";
+import { promisify } from "util";
 
 //needed to pass information on wether or not the promise has been aborted witout 'this'
 class AbortableEmittery extends Emittery {
@@ -10,33 +11,45 @@ class AbortableEmittery extends Emittery {
   }
 }
 
-export default class AbortablePromise<T> extends Promise<T | null> {
+export default class AbortablePromise<T> implements PromiseLike<T> {
   private emitter: AbortableEmittery;
 
+  private result_promise: Promise<T>;
+
   constructor(
     make_generator: (
-      await_or_abort: (
-        promise: Promise<any>,
-        on_abort: () => Promise<unknown>
-      ) => Promise<unknown>
+      await_or_abort: <L>(
+        promise: Promise<L> | AbortablePromise<L>,
+        on_abort?: () => Promise<unknown> | void
+      ) => Promise<L>
     ) => AsyncGenerator
   ) {
     const emitter = new AbortableEmittery();
-    const await_or_abort = (
-      promise: Promise<any>,
-      on_abort: () => Promise<unknown>
-    ) => {
+
+    function await_or_abort<L = any>(promise: AbortablePromise<L>): Promise<L>;
+    function await_or_abort<L = any>(
+      promise: Promise<L> | AbortablePromise<L>,
+      on_abort?: () => Promise<unknown> | void
+    ): Promise<L> {
+      if (promise instanceof AbortablePromise && !on_abort) {
+        on_abort = async () => promise.abort();
+      }
+      if (on_abort === undefined) {
+        throw new Error(
+          "on_abort is required when the first argument is not AbortablePromise"
+        );
+      }
       return new Promise((resolve, reject) => {
         let resolved = false;
         emitter.on("abort", () => {
           if (!resolved) {
-            on_abort();
-            resolve(null);
+            (on_abort as Function)();
+            reject(null);
             resolved = true;
           }
         });
         promise
-          .then((result) => {
+          .then((result: L) => {
             if (!resolved) {
               resolve(result);
               resolved = true;
@@ -44,10 +57,16 @@ export default class AbortablePromise<T> extends Promise<T | null> {
           })
           .catch(reject);
       });
-    };
-    super(async (resolve, reject) => {
+    }
+    this.result_promise = new Promise(async (resolve, reject) => {
       let step_value;
       const generator = make_generator(await_or_abort);
+      console.log("generator:", generator, make_generator);
+      const e = new Error();
+      if (!generator) {
+        console.error(e.stack);
+        console.log("generator:", generator);
+      }
       do {
         if (emitter.aborted) {
           resolve(null);
@@ -63,21 +82,84 @@ export default class AbortablePromise<T> extends Promise<T | null> {
   abort() {
     this.emitter.abort();
   }
+
+  static deadlyRace<L>(promises: AbortablePromise<L>[]): Promise<L> {
+    return new Promise((resolve) => {
+      let resolved = false;
+      const callback = (arg: L) => {
+        if (resolved) return;
+        resolved = true;
+        for (const promise of promises) {
+          console.log("one of the promises resolved! killing the others");
+          promise.abort();
+        }
+        resolve(arg);
+      };
+      for (const promise of promises) {
+        promise.then(callback);
+      }
+    });
+  }
+
+  then<TResult1 = T, TResult2 = never>(
+    onfulfilled?:
+      | ((value: T) => TResult1 | PromiseLike<TResult1>)
+      | undefined
+      | null,
+    onrejected?:
+      | ((reason: any) => TResult2 | PromiseLike<TResult2>)
+      | undefined
+      | null
+  ): PromiseLike<TResult1 | TResult2> {
+    const self = this;
+    return new AbortablePromise(async function* (await_or_abort) {
+      const ret = await await_or_abort(self.result_promise, () => {
+        self.abort();
+      });
+      yield;
+      if (onfulfilled) {
+        onfulfilled(ret);
+      }
+    });
+  }
 }
 
-// const sleep = promisify((timeout: number, callback: (...args: any[]) => void) =>
-// 	setTimeout(callback, timeout)
-// );
+const sleep = promisify((timeout: number, callback: (...args: any[]) => void) =>
+  setTimeout(callback, timeout)
+);
 
 // const a = new AbortablePromise(async function* () {
-// 	yield await sleep(1000);
-// 	console.log("awaited 100");
-// 	yield await sleep(2000);
-// 	console.log("awaited 200");
-// 	yield await sleep(3000);
-// 	console.log("awaited 300");
+//   yield await sleep(1000);
+//   console.log("awaited 100");
+//   yield await sleep(2000);
+//   console.log("awaited 200");
+//   yield await sleep(3000);
+//   console.log("awaited 300");
+// });
+//
+// const a = new AbortablePromise(async function* () {
+//   yield await sleep(1000);
+//   console.log("awaited 100");
+//   yield await sleep(2000);
+//   console.log("awaited 200");
+//   yield await sleep(3000);
+//   console.log("awaited 300");
 // });
 
+function abortableSleep(ms: number): AbortablePromise<void> {
+  return new AbortablePromise(async function* () {
+    await sleep(ms);
+    yield;
+    console.log(`Slept ${ms}.`);
+  });
+}
+
+const b = AbortablePromise.deadlyRace([
+  abortableSleep(1000),
+  abortableSleep(2000),
+  abortableSleep(3000),
+]);
+
 // setTimeout(() => a.abort(), 1500);
 
 // const b = new AbortablePromise(async function* (await_or_abort) {