JavaScript library selection

Same include/exclude rule as Python: this lab measures local handoff. Brokers are category N. Job runners (callable + worker + retry) are not queues.

Decision

Decision	Libraries
Already in	Array, fastq, p-queue (scheduler / Other), steal-deque, opt-in P/S/D
Added	denque, yocto-queue
Out — job / worker frameworks	BullMQ, Bee-Queue, Agenda, Kue, async.queue, @qkitt/queue
Out — schedulers	p-limit, @henrygd/queue, promise-queue (same class as p-queue)
Out — category N	amqplib, kafkajs, ioredis / redis, zeromq, AWS SQS clients

In this lab

Log name	Category	Why
Array	T / locked	push / shift baseline. Already present. O(n) shift.
denque	T / locked	Production O(1) double-ended queue (Redis/Mongo clients). FIFO via push/shift. SPSC only — not worker-thread safe. Added.
yocto-queue	T / locked	Tiny linked-list FIFO, O(1) enqueue/dequeue. Distinct implementation from denque’s ring. SPSC only. Added.
fastq	T / concurrent	In-process work queue. Already present.
p-queue	Other / scheduler	Concurrency limiter. Not ranked as a handoff queue.

denque and yocto-queue skip MPMC cells. Inventing MPMC with a mutex around a single-thread deque would break comparison rule 6.

Out

BullMQ, Bee-Queue, Agenda, and Kue are Redis job runners (category J on a broker). async.queue and p-limit limit concurrency; they do not hand a payload from a producer to a consumer. amqplib / kafkajs / ioredis / zeromq are category N.