310 lines
8.1 KiB
Markdown
310 lines
8.1 KiB
Markdown
|
# fastq
|
||
|
|
|
||
|
|
![ci][ci-url]
|
||
|
|
[![npm version][npm-badge]][npm-url]
|
||
|
|
[![Dependency Status][david-badge]][david-url]
|
||
|
|
|
||
|
|
Fast, in memory work queue.
|
||
|
|
|
||
|
|
Benchmarks (1 million tasks):
|
||
|
|
|
||
|
|
* setImmediate: 812ms
|
||
|
|
* fastq: 854ms
|
||
|
|
* async.queue: 1298ms
|
||
|
|
* neoAsync.queue: 1249ms
|
||
|
|
|
||
|
|
Obtained on node 12.16.1, on a dedicated server.
|
||
|
|
|
||
|
|
If you need zero-overhead series function call, check out
|
||
|
|
[fastseries](http://npm.im/fastseries). For zero-overhead parallel
|
||
|
|
function call, check out [fastparallel](http://npm.im/fastparallel).
|
||
|
|
|
||
|
|
[](https://github.com/feross/standard)
|
||
|
|
|
||
|
|
* <a href="#install">Installation</a>
|
||
|
|
* <a href="#usage">Usage</a>
|
||
|
|
* <a href="#api">API</a>
|
||
|
|
* <a href="#license">Licence & copyright</a>
|
||
|
|
|
||
|
|
## Install
|
||
|
|
|
||
|
|
`npm i fastq --save`
|
||
|
|
|
||
|
|
## Usage (callback API)
|
||
|
|
|
||
|
|
```js
|
||
|
|
'use strict'
|
||
|
|
|
||
|
|
const queue = require('fastq')(worker, 1)
|
||
|
|
|
||
|
|
queue.push(42, function (err, result) {
|
||
|
|
if (err) { throw err }
|
||
|
|
console.log('the result is', result)
|
||
|
|
})
|
||
|
|
|
||
|
|
function worker (arg, cb) {
|
||
|
|
cb(null, arg * 2)
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
## Usage (promise API)
|
||
|
|
|
||
|
|
```js
|
||
|
|
const queue = require('fastq').promise(worker, 1)
|
||
|
|
|
||
|
|
async function worker (arg) {
|
||
|
|
return arg * 2
|
||
|
|
}
|
||
|
|
|
||
|
|
async function run () {
|
||
|
|
const result = await queue.push(42)
|
||
|
|
console.log('the result is', result)
|
||
|
|
}
|
||
|
|
|
||
|
|
run()
|
||
|
|
```
|
||
|
|
|
||
|
|
### Setting "this"
|
||
|
|
|
||
|
|
```js
|
||
|
|
'use strict'
|
||
|
|
|
||
|
|
const that = { hello: 'world' }
|
||
|
|
const queue = require('fastq')(that, worker, 1)
|
||
|
|
|
||
|
|
queue.push(42, function (err, result) {
|
||
|
|
if (err) { throw err }
|
||
|
|
console.log(this)
|
||
|
|
console.log('the result is', result)
|
||
|
|
})
|
||
|
|
|
||
|
|
function worker (arg, cb) {
|
||
|
|
console.log(this)
|
||
|
|
cb(null, arg * 2)
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
### Using with TypeScript (callback API)
|
||
|
|
|
||
|
|
```ts
|
||
|
|
'use strict'
|
||
|
|
|
||
|
|
import * as fastq from "fastq";
|
||
|
|
import type { queue, done } from "fastq";
|
||
|
|
|
||
|
|
type Task = {
|
||
|
|
id: number
|
||
|
|
}
|
||
|
|
|
||
|
|
const q: queue<Task> = fastq(worker, 1)
|
||
|
|
|
||
|
|
q.push({ id: 42})
|
||
|
|
|
||
|
|
function worker (arg: Task, cb: done) {
|
||
|
|
console.log(arg.id)
|
||
|
|
cb(null)
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
### Using with TypeScript (promise API)
|
||
|
|
|
||
|
|
```ts
|
||
|
|
'use strict'
|
||
|
|
|
||
|
|
import * as fastq from "fastq";
|
||
|
|
import type { queueAsPromised } from "fastq";
|
||
|
|
|
||
|
|
type Task = {
|
||
|
|
id: number
|
||
|
|
}
|
||
|
|
|
||
|
|
const q: queueAsPromised<Task> = fastq.promise(asyncWorker, 1)
|
||
|
|
|
||
|
|
q.push({ id: 42}).catch((err) => console.error(err))
|
||
|
|
|
||
|
|
async function asyncWorker (arg: Task): Promise<void> {
|
||
|
|
// No need for a try-catch block, fastq handles errors automatically
|
||
|
|
console.log(arg.id)
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
## API
|
||
|
|
|
||
|
|
* <a href="#fastqueue"><code>fastqueue()</code></a>
|
||
|
|
* <a href="#push"><code>queue#<b>push()</b></code></a>
|
||
|
|
* <a href="#unshift"><code>queue#<b>unshift()</b></code></a>
|
||
|
|
* <a href="#pause"><code>queue#<b>pause()</b></code></a>
|
||
|
|
* <a href="#resume"><code>queue#<b>resume()</b></code></a>
|
||
|
|
* <a href="#idle"><code>queue#<b>idle()</b></code></a>
|
||
|
|
* <a href="#length"><code>queue#<b>length()</b></code></a>
|
||
|
|
* <a href="#getQueue"><code>queue#<b>getQueue()</b></code></a>
|
||
|
|
* <a href="#kill"><code>queue#<b>kill()</b></code></a>
|
||
|
|
* <a href="#killAndDrain"><code>queue#<b>killAndDrain()</b></code></a>
|
||
|
|
* <a href="#error"><code>queue#<b>error()</b></code></a>
|
||
|
|
* <a href="#concurrency"><code>queue#<b>concurrency</b></code></a>
|
||
|
|
* <a href="#drain"><code>queue#<b>drain</b></code></a>
|
||
|
|
* <a href="#empty"><code>queue#<b>empty</b></code></a>
|
||
|
|
* <a href="#saturated"><code>queue#<b>saturated</b></code></a>
|
||
|
|
* <a href="#promise"><code>fastqueue.promise()</code></a>
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="fastqueue"></a>
|
||
|
|
### fastqueue([that], worker, concurrency)
|
||
|
|
|
||
|
|
Creates a new queue.
|
||
|
|
|
||
|
|
Arguments:
|
||
|
|
|
||
|
|
* `that`, optional context of the `worker` function.
|
||
|
|
* `worker`, worker function, it would be called with `that` as `this`,
|
||
|
|
if that is specified.
|
||
|
|
* `concurrency`, number of concurrent tasks that could be executed in
|
||
|
|
parallel.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="push"></a>
|
||
|
|
### queue.push(task, done)
|
||
|
|
|
||
|
|
Add a task at the end of the queue. `done(err, result)` will be called
|
||
|
|
when the task was processed.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="unshift"></a>
|
||
|
|
### queue.unshift(task, done)
|
||
|
|
|
||
|
|
Add a task at the beginning of the queue. `done(err, result)` will be called
|
||
|
|
when the task was processed.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="pause"></a>
|
||
|
|
### queue.pause()
|
||
|
|
|
||
|
|
Pause the processing of tasks. Currently worked tasks are not
|
||
|
|
stopped.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="resume"></a>
|
||
|
|
### queue.resume()
|
||
|
|
|
||
|
|
Resume the processing of tasks.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="idle"></a>
|
||
|
|
### queue.idle()
|
||
|
|
|
||
|
|
Returns `false` if there are tasks being processed or waiting to be processed.
|
||
|
|
`true` otherwise.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="length"></a>
|
||
|
|
### queue.length()
|
||
|
|
|
||
|
|
Returns the number of tasks waiting to be processed (in the queue).
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="getQueue"></a>
|
||
|
|
### queue.getQueue()
|
||
|
|
|
||
|
|
Returns all the tasks be processed (in the queue). Returns empty array when there are no tasks
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="kill"></a>
|
||
|
|
### queue.kill()
|
||
|
|
|
||
|
|
Removes all tasks waiting to be processed, and reset `drain` to an empty
|
||
|
|
function.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="killAndDrain"></a>
|
||
|
|
### queue.killAndDrain()
|
||
|
|
|
||
|
|
Same than `kill` but the `drain` function will be called before reset to empty.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="error"></a>
|
||
|
|
### queue.error(handler)
|
||
|
|
|
||
|
|
Set a global error handler. `handler(err, task)` will be called
|
||
|
|
each time a task is completed, `err` will be not null if the task has thrown an error.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="concurrency"></a>
|
||
|
|
### queue.concurrency
|
||
|
|
|
||
|
|
Property that returns the number of concurrent tasks that could be executed in
|
||
|
|
parallel. It can be altered at runtime.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="drain"></a>
|
||
|
|
### queue.drain
|
||
|
|
|
||
|
|
Function that will be called when the last
|
||
|
|
item from the queue has been processed by a worker.
|
||
|
|
It can be altered at runtime.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="empty"></a>
|
||
|
|
### queue.empty
|
||
|
|
|
||
|
|
Function that will be called when the last
|
||
|
|
item from the queue has been assigned to a worker.
|
||
|
|
It can be altered at runtime.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="saturated"></a>
|
||
|
|
### queue.saturated
|
||
|
|
|
||
|
|
Function that will be called when the queue hits the concurrency
|
||
|
|
limit.
|
||
|
|
It can be altered at runtime.
|
||
|
|
|
||
|
|
-------------------------------------------------------
|
||
|
|
<a name="promise"></a>
|
||
|
|
### fastqueue.promise([that], worker(arg), concurrency)
|
||
|
|
|
||
|
|
Creates a new queue with `Promise` apis. It also offers all the methods
|
||
|
|
and properties of the object returned by [`fastqueue`](#fastqueue) with the modified
|
||
|
|
[`push`](#pushPromise) and [`unshift`](#unshiftPromise) methods.
|
||
|
|
|
||
|
|
Node v10+ is required to use the promisified version.
|
||
|
|
|
||
|
|
Arguments:
|
||
|
|
* `that`, optional context of the `worker` function.
|
||
|
|
* `worker`, worker function, it would be called with `that` as `this`,
|
||
|
|
if that is specified. It MUST return a `Promise`.
|
||
|
|
* `concurrency`, number of concurrent tasks that could be executed in
|
||
|
|
parallel.
|
||
|
|
|
||
|
|
<a name="pushPromise"></a>
|
||
|
|
#### queue.push(task) => Promise
|
||
|
|
|
||
|
|
Add a task at the end of the queue. The returned `Promise` will be fulfilled (rejected)
|
||
|
|
when the task is completed successfully (unsuccessfully).
|
||
|
|
|
||
|
|
This promise could be ignored as it will not lead to a `'unhandledRejection'`.
|
||
|
|
|
||
|
|
<a name="unshiftPromise"></a>
|
||
|
|
#### queue.unshift(task) => Promise
|
||
|
|
|
||
|
|
Add a task at the beginning of the queue. The returned `Promise` will be fulfilled (rejected)
|
||
|
|
when the task is completed successfully (unsuccessfully).
|
||
|
|
|
||
|
|
This promise could be ignored as it will not lead to a `'unhandledRejection'`.
|
||
|
|
|
||
|
|
<a name="drained"></a>
|
||
|
|
#### queue.drained() => Promise
|
||
|
|
|
||
|
|
Wait for the queue to be drained. The returned `Promise` will be resolved when all tasks in the queue have been processed by a worker.
|
||
|
|
|
||
|
|
This promise could be ignored as it will not lead to a `'unhandledRejection'`.
|
||
|
|
|
||
|
|
## License
|
||
|
|
|
||
|
|
ISC
|
||
|
|
|
||
|
|
[ci-url]: https://github.com/mcollina/fastq/workflows/ci/badge.svg
|
||
|
|
[npm-badge]: https://badge.fury.io/js/fastq.svg
|
||
|
|
[npm-url]: https://badge.fury.io/js/fastq
|
||
|
|
[david-badge]: https://david-dm.org/mcollina/fastq.svg
|
||
|
|
[david-url]: https://david-dm.org/mcollina/fastq
|