Fastseries NPM

fastseries

Zero-overhead series function call for node.js. Also supports each and map!

If you need zero-overhead parallel function call, check out fastparallel.

Example for series call

var series = require('fastseries')({
  // if you want the results, then here you are
  results: true
})

series(
  {}, // what will be this in the functions
  [something, something, something], // functions to call
  42, // the first argument of the functions
  done // the function to be called when the series ends
)

function late (arg, cb) {
  console.log('finishing', arg)
  cb(null, 'myresult-' + arg)
}

function something (arg, cb) {
  setTimeout(late, 1000, arg, cb)
}

function done (err, results) {
  console.log('series completed, results:', results)
}

Example for each and map calls

var series = require('fastseries')({
  // if you want the results, then here you are
  // passing false disables map
  results: true
})

series(
  {}, // what will be this in the functions
  something, // functions to call
  [1, 2, 3], // the first argument of the functions
  done // the function to be called when the series ends
)

function late (arg, cb) {
  console.log('finishing', arg)
  cb(null, 'myresult-' + arg)
}

function something (arg, cb) {
  setTimeout(late, 1000, arg, cb)
}

function done (err, results) {
  console.log('series completed, results:', results)
}

Caveats

The done function will be called only once, even if more than one error happen.

This library works by caching the latest used function, so that running a new series does not cause any memory allocations.

Benchmarks

Benchmark for doing 3 calls setImmediate 1 million times:

benchSetImmediate*1000000: 2460.623ms
benchAsyncSeries*1000000: 3064.569ms
benchAsyncEachSeries*1000000: 2913.525ms
benchAsyncMapSeries*1000000: 3020.794ms
benchNeoSeries*1000000: 2617.064ms
benchNeoEachSeries*1000000: 2621.672ms
benchNeoMapSeries*1000000: 2611.294ms
benchTinyEachAsync*1000000: 2706.457ms
benchFastSeries*1000000: 2540.653ms
benchFastSeriesNoResults*1000000: 2538.674ms
benchFastSeriesEach*1000000: 2534.856ms
benchFastSeriesEachResults*1000000: 2545.394ms

Benchmarks taken on Node 12.16.1 on a dedicated server.

See bench.js for mode details.