FnChain

Serial control flow with explicit progression

Installation

$ npm install fnchain

Usage

new FnChain(Array, Function)

• Array of functions each one in the form function (p1, p2, pN, ..., next), where next is the step callback
• Final callback in the canonical form function (err, p1, p2, pN, ...)

Each function in the chain should call the step callback in order to advance the execution. You can also stop the chain passing true as last parameter to the above mentioned step callback (look at the examples)

Methods

FnChain.call(p1, p2, pN, ...)

Fire the chain execution calling each function with the provided arguments Nothing related with Function.call

FnChain.addTask(Function)

Push a new task to the end of the chain (available even with the chain in progress)

Examples

Stop on error

var FnChain = require('chain');

new FnChain([
  function (p1, p2, next) {
    next()
  },
  function (p1, p2, next) {
    next(new Error('TerribleError'))
  },
  function (p1, p2, next) {
    // never fired
    next()
  }
], function (err, p1, p2) {
  err.message === 'TerribleError'
}).call('foo', 'bar')

Explicit stop

new FnChain([
  function (p1, p2, next) {
    next()
  },
  function (p1, p2, next) {
    next(null, true) // stop the chain
  },
  function (p1, p2, next) {
    // never fired
    next()
  }
], function (err, p1, p2) {
  err === undefined
}).call('foo', 'bar')

In progress addTask

var chain = new FnChain([
  function (p1, p2, next) {
    next()
  },
  function (p1, p2, next) {
    chain.addTask(function (p1, p2, next) {
      // executed at the end
      next()
    })
    next()
  },
  function (p1, p2, next) {
    // never fired
    next()
  }
], function (err, p1, p2) {
  
}).call('foo', 'bar')

License

This software is released under the MIT license cited below.

Copyright (c) 2010 Kilian Ciuffolo, [email protected]. All Rights Reserved.

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the 'Software'), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.