fastfall

fastfall

call your callbacks in a waterfall, without overhead

Benchmark for doing 3 calls setImmediate 100 thousands times:

• non-reusable setImmediate: 407ms
• async.waterfall: 1203ms
• run-waterfall: 1432ms
• insync.wasterfall: 1570ms
• neo-async.wasterfall: 445ms
• waterfallize: 757ms
• fastfall: 432ms
• fastfall compiled: 428ms

These benchmarks where taken via bench.js on node 4.2.2, on a MacBook Pro Retina 2014 (i7, 16GB of RAM).

If you need zero-overhead series function call, check out fastseries, for parallel calls check out fastparallel, and for a fast work queue use fastq.

Install

npm install fastfall --save

Usage

var fall = require('fastfall')()

fall([
  function a (cb) {
    console.log('called a')
    cb(null, 'a')
  },
  function b (a, cb) {
    console.log('called b with:', a)
    cb(null, 'a', 'b')
  },
  function c (a, b, cb) {
    console.log('called c with:', a, b)
    cb(null, 'a', 'b', 'c')
  }], function result (err, a, b, c) {
    console.log('result arguments', arguments)
  })

You can also set this when you create a fall:

var that = { hello: 'world' }
var fall = require('fastfall')(that)

fall([a, b, c], result)

function a (cb) {
  console.log(this)
  console.log('called a')
  cb(null, 'a')
}

function b (a, cb) {
  console.log('called b with:', a)
  cb(null, 'a', 'b')
}

function c (a, b, cb) {
  console.log('called c with:', a, b)
  cb(null, 'a', 'b', 'c')
}

function result (err, a, b, c) {
  console.log('result arguments', arguments)
}

You can also set this when you run a task:

var that = { hello: 'world' }
var fall = require('fastfall')()

fall(new State('world'), [
  a, b, c,
], console.log)

function State (value) {
  this.value = value
}

function a (cb) {
  console.log(this.value)
  console.log('called a')
  cb(null, 'a')
}

function b (a, cb) {
  console.log('called b with:', a)
  cb(null, 'a', 'b')
}

function c (a, b, cb) {
  console.log('called c with:', a, b)
  cb(null, 'a', 'b', 'c')
}

Compile a waterfall

var fall = require('fastfall')([
  function a (arg, cb) {
    console.log('called a')
    cb(null, arg)
  },
  function b (a, cb) {
    console.log('called b with:', a)
    cb(null, 'a', 'b')
  },
  function c (a, b, cb) {
    console.log('called c with:', a, b)
    cb(null, 'a', 'b', 'c')
  }])

// a compiled fall supports arguments too!
fall(42, function result (err, a, b, c) {
  console.log('result arguments', arguments)
})

You can set this by doing:

var that = { hello: 'world' }
var fall = require('fastfall')(that, [
  function a (arg, cb) {
    console.log('this is', this)
    console.log('called a')
    cb(null, arg)
  },
  function b (a, cb) {
    console.log('called b with:', a)
    cb(null, 'a', 'b')
  },
  function c (a, b, cb) {
    console.log('called c with:', a, b)
    cb(null, 'a', 'b', 'c')
  }])

// a compiled fall supports arguments too!
fall(42, function result (err, a, b, c) {
  console.log('result arguments', arguments)
})

or you can simply attach it to an object:

var that = { hello: 'world' }
that.doSomething = require('fastfall')([
  function a (arg, cb) {
    console.log('this is', this)
    console.log('called a')
    cb(null, arg)
  },
  function b (a, cb) {
    console.log('called b with:', a)
    cb(null, 'a', 'b')
  },
  function c (a, b, cb) {
    console.log('called c with:', a, b)
    cb(null, 'a', 'b', 'c')
  }])

// a compiled fall supports arguments too!
that.doSomething(42, function result (err, a, b, c) {
  console.log('this is', this)
  console.log('result arguments', arguments)
})

API

fastfall([this], [functions])

Creates a fall, it can either be pre-filled with a this value and an array of functions.

If there is no list of functions, a not-compiled fall is returned, if there is a list of function a compiled fall is returned.

fall([this], functions, [done])

Calls the functions in a waterfall, forwarding the arguments from one to another. Calls done when it has finished.

fall(args..., [done])

Calls the compiled functions in a waterfall, forwarding the arguments from one to another. Additionally, a user can specify some arguments for the first function, too. Calls done when it has finished.

License

MIT