Conseq

node-conseq is a small, simple library for handling the nesting explosion. It is heavily inspired by node-seq.

node-conseq can handle node-style EventEmitter callbacks as well as error-as-first-argument callbacks.

Examples

var Seq = require('conseq')
var http = require('http')

Seq()
  .seq(function () {
    http.get({host: 'www.google.com', path: '/index.html'}, this.next)
      .on('error', this.error)
  })
  .seq(function (res) {
    if (res.statusCode == 200) {
      res.on('data', this.next)
    } else {
      this.error({message: 'Error ' + res.statusCode})
    }
  })
  .seq(function (data) {
    console.log("Got data: " + data)
  })
  .catch(function (err) {
    console.log("there was an error! " + JSON.stringify(err))
  })

Use this.next as a callback to proceed to the next function in the chain. Use this.error as a callback to be called in an error condition. this.combined is a convenience, meaning:

function (err, ...) {
  if (err) this.error(err)
  else this.next(...)
}

Parallel function callbacks

Seq()
  .seq(function () {
    fs.stat('/etc/passwd', this.parcombined)
    fs.stat(process.env['HOME'], this.parcombined)
  })
  .seq(function (results) {
    console.log('/etc/passwd', results[0].isFile() ? "is" : "is not", "a file")
    console.log(process.env['HOME'], results[1].isDirectory() ? "is" : "is not", "a directory")
  })

parcombined works like combined does for single action steps. par is the parallel equivalent of next, and parerror for error.

Installing

Install with npm install conseq. If you want to run the tests, you'll need to install zap.