parallelFindIndex.ts

concept-code/parallelFindIndex.ts

@@ -0,0 +1,27 @@
+import { thread } from 'value-script';
+
+export default function parallelFindIndex<Value>(
+  values: Value[],
+  predicate: (value: Value) => boolean,
+  concurrencyLimit = 10,
+): number | undefined {
+  let poolSize = Math.min(values.length, concurrencyLimit);
+
+  const pool = values
+    .slice(0, poolSize)
+    .map(v => thread(() => predicate(v)));
+
+  for (let i = 0; i < values.length; i++) {
+    if (pool[i % poolSize]()) {
+      // When exiting here, everything gets dereferenced, which will notify all
+      // the other threads to stop working and clean up
+      return i;
+    }
+
+    if (i + poolSize < values.length) {
+      pool[i % poolSize] = thread(() => predicate(values[i + poolSize]));
+    }
+  }
+
+  return undefined;
+}