after
after - tiny flow control
Last updated 4 years ago by raynos .
MIT · Repository · Bugs · Original npm · Tarball · package.json
$ cnpm install after 
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After Build Status

Invoke callback after n calls

Status: production ready

Example

var after = require("after")
var db = require("./db") // some db.

var updateUser = function (req, res) {
  // use after to run two tasks in parallel,
  // namely get request body and get session
  // then run updateUser with the results
  var next = after(2, updateUser)
  var results = {}
  
  getJSONBody(req, res, function (err, body) {
    if (err) return next(err)
    
    results.body = body
    next(null, results)
  })
  
  getSessionUser(req, res, function (err, user) {
    if (err) return next(err)
    
    results.user = user
    next(null, results)
  })
  
  // now do the thing!
  function updateUser(err, result) {
    if (err) {
      res.statusCode = 500
      return res.end("Unexpected Error")
    }
    
    if (!result.user || result.user.role !== "admin") {
      res.statusCode = 403
      return res.end("Permission Denied")
    }
    
    db.put("users:" + req.params.userId, result.body, function (err) {
      if (err) {
        res.statusCode = 500
        return res.end("Unexpected Error")
      }
      
      res.statusCode = 200
      res.end("Ok")  
    })   
  }
}

Naive Example

var after = require("after")
    , next = after(3, logItWorks)

next()
next()
next() // it works

function logItWorks() {
    console.log("it works!")
}

Example with error handling

var after = require("after")
    , next = after(3, logError)

next()
next(new Error("oops")) // logs oops
next() // does nothing

// This callback is only called once.
// If there is an error the callback gets called immediately
// this avoids the situation where errors get lost.
function logError(err) {
    console.log(err)
}

Installation

npm install after

Tests

npm test

Contributors

  • Raynos
  • defunctzombie

MIT Licenced

Current Tags

  • 0.8.2                                ...           latest (4 years ago)

19 Versions

  • 0.8.2                                ...           4 years ago
  • 0.8.1                                ...           7 years ago
  • 0.7.0                                ...           7 years ago
  • 0.6.0                                ...           8 years ago
  • 0.5.0                                ...           8 years ago
  • 0.4.1                                ...           8 years ago
  • 0.4.0                                ...           8 years ago
  • 0.3.4                                ...           8 years ago
  • 0.3.3                                ...           8 years ago
  • 0.3.2                                ...           8 years ago
  • 0.3.1                                ...           8 years ago
  • 0.1.3                                ...           9 years ago
  • 0.2.0                                ...           9 years ago
  • 0.1.6                                ...           9 years ago
  • 0.1.5                                ...           9 years ago
  • 0.1.4                                ...           9 years ago
  • 0.1.0                                ...           9 years ago
  • 0.1.8                                ...           9 years ago
  • 0.1.7                                ...           9 years ago
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