run-series

What is run-series?

The run-series npm package is a utility that allows you to run an array of functions in series, each one running once the previous function has completed. If any functions in the series pass an error to its callback, no more functions are run, and the main callback is immediately called with the error. This package is particularly useful for managing sequences of asynchronous tasks in a clean and straightforward manner.

What are run-series's main functionalities?

Running tasks in series

This feature allows you to run multiple tasks one after another. Each task is a function that takes a callback as its only argument. Once a task completes, it calls the callback, optionally passing an error and results. If a task passes an error, the series is stopped, and the final callback is called with the error. Otherwise, after all tasks have completed, the final callback is called with an array of results.

const series = require('run-series');

series([
  function(callback) {
    // Task 1
    callback(null, 'result of task 1');
  },
  function(callback) {
    // Task 2
    callback(null, 'result of task 2');
  }
], function(err, results) {
  if (err) throw err;
  console.log(results); // ['result of task 1', 'result of task 2']
});

Other packages similar to run-series

async

The 'async' package provides a wide range of functions for working with asynchronous JavaScript, including a 'series' method that behaves similarly to run-series. However, 'async' offers much more functionality beyond just running tasks in series, such as parallel execution, waterfall flows, and more, making it a more versatile choice for complex asynchronous control flow.

neo-async

Neo-async is a drop-in replacement for the 'async' library, designed to be faster and more lightweight. It offers a 'series' function similar to that of run-series and async, but with performance improvements and additional features for handling asynchronous operations, making it a good choice for performance-critical applications that require complex flow control.

README

run-series

Run an array of functions in series

install

npm install run-series

usage

series(tasks, [callback])

Run the functions in the tasks array in series, each one running once the previous function has completed. If any functions in the series pass an error to its callback, no more functions are run, and callback is immediately called with the value of the error. Otherwise, callback receives an array of results when tasks have completed.

arguments

• tasks - An array containing functions to run, each function is passed a callback(err, result) which it must call on completion with an error err (which can be null) and an optional result value.
• callback(err, results) - An optional callback to run once all the functions have completed. This function gets a results array containing all the result arguments passed to the task callbacks.

example

var series = require('run-series')

series([
  function (callback) {
    // do some stuff ...
    callback(null, 'one')
  },
  function (callback) {
    // do some stuff ...
    callback(null, 'two')
  }
],
// optional callback
function (err, results) {
  // the results array will equal ['one','two']
})

waterfall(tasks, [callback])

Runs the tasks array of functions in series, each passing their results to the next in the array. However, if any of the tasks pass an error to their own callback, the next function is not executed, and the main callback is immediately called with the error.

arguments

• tasks - An array of functions to run, each function is passed a callback(err, result1, result2, ...) it must call on completion. The first argument is an error (which can be null) and any further arguments will be passed as arguments in order to the next task.
• callback(err, [results]) - An optional callback to run once all the functions have completed. This will be passed the results of the last task's callback.

example

var series = require('run-series')

series.waterfall([
  function (callback) {
    callback(null, 'one', 'two')
  },
  function (arg1, arg2, callback) {
    // arg1 now equals 'one' and arg2 now equals 'two'
    callback(null, 'three')
  },
  function (arg1, callback) {
    // arg1 now equals 'three'
    callback(null, 'done', 'wohoo')
  }
], function (err, result1, result2) {
   // result1 now equals 'done'
   // result2 now equals 'wohoo'
})

This module is basically equavalent to async.series and async.waterfall, but it's handy to just have the functions you need instead of the kitchen sink. Modularity! Especially handy if you're serving to the browser and need to reduce your javascript bundle size.

Works great in the browser with browserify!

license

MIT. Copyright (c) Feross Aboukhadijeh.