signal; helpers

src/signal.ts

@@ -1,4 +1,3 @@
-
 /**
  * Ensures that a passed {@link Function} is called when the given {@link AbortSignal} is aborted.
  *
@@ -11,3 +10,38 @@ export function handleAbortSignalAbort(signal: AbortSignal | undefined, fn: () =
     signal?.addEventListener('abort', fn);
   }
 }
+
+/**
+ * Returns a {@link Promise} for the abort of the passed {@link AbortSignal}. This may be
+ * immediately.
+ */
+export function promiseForSignal<T = never>(
+  signal: AbortSignal,
+  resolveWith: Promise<T> | T = Promise.reject<T>(new Error('aborted')),
+): Promise<T> {
+  if (signal.aborted) {
+    return Promise.resolve(resolveWith);
+  } else {
+    return new Promise((resolve) => {
+      signal.addEventListener('abort', () => resolve(resolveWith));
+    });
+  }
+}
+
+/**
+ * Returns a new {@link AbortSignal} that can be individually aborted, but which is also tied to
+ * the lifetime of the passed signal.
+ *
+ * If the passed signal is already aborted, returns it directly.
+ */
+export function derivedSignal(previous?: AbortSignal) {
+  if (previous?.aborted) {
+    return { signal: previous, abort: () => {} };
+  }
+
+  const c = new AbortController();
+  const abort = () => c.abort();
+
+  previous?.addEventListener('abort', abort);
+  return { signal: c.signal, abort };
+}

tsconfig.json

@@ -5,9 +5,9 @@
 
     // if you'd like to warn if you're using modern features, change these
     // both to e.g., "es2017"
-    "module": "esnext",
-    "target": "esnext",
-    "moduleResolution": "nodenext",
+    "module": "NodeNext",
+    "target": "ESNext",
+    "moduleResolution": "NodeNext",
     "esModuleInterop": true,
 
     "allowSyntheticDefaultImports": true,