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    async-control

    0.5.0 • Public • Published

    async-control npmjs.com The MIT License

    Ultimate asynchronous control flow goodness with built-in hook system and compose, series, define and parallel methods. Uses async.map and async.mapSeries methods. Allows passing custom iterator function.

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    Install

    npm i async-control --save
    

    Usage

    For more use-cases see the tests

    const fs = require('fs')
    const asyncControl = require('async-control')
     
    asyncControl.series([
      function one (next) {
        console.log('first')
        fs.readFile('package.json', 'utf8', next)
      },
      function two (next) {
        setTimeout(function () {
          console.log('second')
          fs.stat('not exist', next)
        }, 100)
      },
      function three (next) {
        console.log('third')
        next(null, 123)
      }
    ], {settle: false}, function done (err, res) {
      // => first
      // => second
      // => third
     
      console.log('err:', err)
      // => if `options.settle` is true - `undefined`, otherwise thrown Error
      console.log('res:', res) // => array of results
      // => res[0] is content of package.json file
      // => res[1] is `undefined`, because second function throws Error (ENOENT)
      // if `options.settle` is true
      // - res[1] will be Error
      // - res[2] will be 123
    })

    AsyncControl

    Initialize AsyncControl with options to control enabling/disabling options.settle, passing custom iterator and pass different hooks - before, after, etc.

    Params

    • options {Object=}

    .series

    Iterate over value in series flow. The async.mapSeries method is used.

    Params

    • value {Object|Array|Function}: The value to iterate over.
    • options {Object=}: Can pass different hooks - before, after, beforeEach, afterEach.
    • done {Function=}: If not passed, thunk is returned (function that accepts callback).
    • returns {Function}: Or undefined if done is passed.

    Example

    var fs = require('fs')
    var asyncControl = require('async-control')
     
    asyncControl.series([
      function one (cb) {
        cb(null, 'foo')
      },
      function two (cb) {
        fs.readFile('not exist', cb)
      },
      function three (cb) {
        cb(null, 'bar')
      }
    ], console.log) //=> ENOENT Error, ['foo', undefined]

    .parallel

    Iterate over value in parallel flow. The async.map method is used.

    Params

    • value {Object|Array|Function}: The value to iterate over.
    • options {Object=}: Can pass different hooks - before, after, beforeEach, afterEach.
    • done {Function=}: If not passed, thunk is returned (function that accepts callback).
    • returns {Function}: Or undefined if done is passed.

    Example

    var fs = require('fs')
    var asyncControl = require('async-control')
     
    asyncControl.parallel([
      function one (next) {
        setTimeout(function () {
          console.log('first')
          next(null, 100)
        }, Math.random() * 50)
      },
      function two (next) {
        setTimeout(function () {
          console.log('second')
          next(null, 700)
        }, Math.random() * 200)
      },
      function three (next) {
        setTimeout(function () {
          console.log('third')
          next(null, 2000)
        }, 0)
      }
    ], function done (err, res) {
      // => third
      // => first
      // => second
     
      console.log(err) // => null
      console.log(res) // => [2000, 100, 700]
    })

    .compose

    Compose series or parallel method. Can be used to create settleSeries or settleParallel methods for example.

    Params

    • flow {String}: Type of flow, one of 'series' or 'parallel'.
    • options {Object=}: Can pass different hooks - before, after, beforeEach, afterEach.
    • returns {Function}: Composed series or parallel method, depends on flow.

    Example

    var fs = require('fs')
    var asyncControl = require('async-control')
     
    // the internal `.series` method is created this way - using `.compose`
    var series = asyncControl.compose('series')
    series([
      function one (cb) {
        cb(null, 123)
      },
      function two (cb) {
        fs.readFile('not exist', cb)
      },
      function three (cb) {
        cb(null, 456)
      }
    ], {settle: true}, console.log) //=> null, [123, ENOENT Error, 456]

    Custom iterator

    Below example shows how to create your own iterator using asyncControl.define method. This also can be done by passing function to options.iterator. It recieves app and options and must return function which is directly passed to async.map and/or async.mapSeries methods.

    Params

    • app {Object}: instance of AsyncControl
    • opts {Object}: the app options
    • returns {Function}: iterator passed directly to async.map / async.mapSeries

    Example

    const util = require('util')
    const asyncControl = require('async-control')
     
    asyncControl.define('iterator', function customIterator (app, options) {
      // this === app
      return iterator (fn, next) {
        // this === app
        console.log(util.inspect(fn))
        next()
      }
    })
    asyncControl.series([
      function first (next) { next(null, 1) },
      function second (next) { next(null, 2) },
      function third (next) { next(null, 3) }
    ], function (err, res) {
      // => [Function: first]
      // => [Function: second]
      // => [Function: third]
     
      console.log(err, res)
      // => null, [1, 2, 3]
    })

    Contributing

    Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
    But before doing anything, please read the CONTRIBUTING.md guidelines.

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    Install

    npm i async-control

    DownloadsWeekly Downloads

    2

    Version

    0.5.0

    License

    MIT

    Last publish

    Collaborators

    • vanchoy
    • tunnckocore