Offload functions to worker threads with shared memory primitives for Node.js.
docs: document isTask() and worker affinity in README
Add a paragraph under Load Balancing showing how isTask() narrows a
task to a specific moroutine's descriptor shape, with a keyAffinity
balancer example. Link to examples/worker-affinity for the full demo.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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README.md
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README.md
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Each `WorkerHandle` exposes `activeCount` (in-flight tasks) and `thread` (the underlying `worker_threads.Worker`) for building custom strategies.
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`isTask(moroutine, task)` narrows a task to the descriptor type produced by a specific moroutine — useful inside a balancer to route by task kind or by a key in the args. For example, a worker-affinity balancer can hash a shard key out of the args so that every call for the same key hits the worker that already has its state loaded:
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```ts
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import { isTask, roundRobin } from 'moroutine';
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import type { Balancer } from 'moroutine';
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import { increment, read } from './counter.ts';
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export function keyAffinity(): Balancer {
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const fallback = roundRobin();
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return {
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select(workers, task) {
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let key: string | undefined;
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if (isTask(increment, task)) key = task.args[0];
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else if (isTask(read, task)) key = task.args[0];
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if (key === undefined) return fallback.select(workers, task);
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return workers[hash(key) % workers.length];
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},
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};
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}
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```
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Inside the `isTask` branch, `task.args` is typed as the moroutine's argument tuple (e.g. `[key: string, n: number]` for `increment`). See [`examples/worker-affinity`](examples/worker-affinity) for the full demo, including per-worker state that only stays consistent under affinity routing.
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### Dedicated Workers
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Awaiting a task directly (without a pool) runs it on a dedicated worker thread, one per moroutine function.