fastify-queue

An async queue for Fastify.

Usage

npm i @autotelic/fastify-queue

Example

import fastifyQueue from '@autotelic/fastify-queue'

function myRoute (fastify, opts) {
  fastify.register(fastifyQueue)

  fastify.post('/example', async (request, reply) => {
    reply.queue.add('async-action-one', reply.asyncAction())
    reply.queue.add('async-action-two', reply.asyncActionTwo())
    reply.queue.add('async-action-three', reply.asyncActionThree())
    // Manual resolution optional - queue will otherwise resolve in onResponse hook.
    const results = await reply.queue.resolve()
    reply.status(200)
  })
}

API

Plugin opts

fastify-queue accepts the following optional configuration:

• initializer: (key: PropertyKey, value: unknown, reply: FastifyReply) => unknown | Promise<unknown>

  • Called each time an item is added to the queue. The value returned will be the value added to the queue.

• resolver: (key: PropertyKey, value: unknown, reply: FastifyReply) => unknown | PromiseLike<unknown>

  • Called each time an item in the queue is resolved. value is the resolved value of an item in the queue.

• onError: (error: Error, reply: FastifyReply) => void

  • Called if an error occurs while resolving the queue. Defaults to fastify.log.error(error).

• onResolved: (result: Map<PropertyKey, unknown>, reply: FastifyReply) => void | Promise<void>

  • Called after the queue has successfully resolved. result is the resolved queue.

• queueName: string

  • Determines the name of the reply decorator added by the plugin. Defaults to 'queue'.

• concurrency: number

  • Max number of concurrently pending promises. Defaults to Infinity.
  • This value is passed directly to p-props options param.

• stopOnError: boolean

  • When set to false, errors thrown while resolving items in the queue will be accumulated. Once all items in the queue have settled, a single aggregated error will be thrown.
  • This value is passed directly to p-props options param.

Reply Decorator

fastify-queue adds a queue (or the value of opts.queueName) reply decorator containing the following properties:

• add: (key: PropertyKey, value: unknown) => void

  • Used to add items to the queue.

• resolve: (cb?: typeof opts.onResolved) => Promise<void>

  • Used to manually resolve the queue. cb defaults to opts.onResolved
  • If cb is provided it will be called instead of opts.onResolved
  • result param of cb is the resolved queue
  • fastify-queue will automatically resolve the queue in an onResponse hook, if this has not already been called.

• contents: Map<PropertyKey, unknown>

  • The queue Map instance.