https://github.com/stdlib-js/utils-async-series-waterfall
Execute functions in series, passing the results of one function as arguments to the next function.
https://github.com/stdlib-js/utils-async-series-waterfall
async consecutive control fcns flow functions javascript node node-js nodejs run sequential series stdlib util utilities utils waterfall
Last synced: 16 days ago
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Execute functions in series, passing the results of one function as arguments to the next function.
- Host: GitHub
- URL: https://github.com/stdlib-js/utils-async-series-waterfall
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-14T13:39:47.000Z (about 5 years ago)
- Default Branch: main
- Last Pushed: 2026-06-03T03:52:13.000Z (about 1 month ago)
- Last Synced: 2026-06-03T05:17:48.422Z (about 1 month ago)
- Topics: async, consecutive, control, fcns, flow, functions, javascript, node, node-js, nodejs, run, sequential, series, stdlib, util, utilities, utils, waterfall
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 1.49 MB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
- Notice: NOTICE
Awesome Lists containing this project
README
About stdlib...
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.
The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
# Waterfall
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Execute functions in series, passing the results of one function as arguments to the next function.
## Installation
```bash
npm install @stdlib/utils-async-series-waterfall
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var waterfall = require( '@stdlib/utils-async-series-waterfall' );
```
#### waterfall( fcns, clbk\[, thisArg] )
Executes `functions` in series, passing the results of one `function` as arguments to the next `function`.
```javascript
function foo( next ) {
next( null, 'beep' );
}
function bar( str, next ) {
console.log( str );
// => 'beep'
next();
}
function done( error ) {
if ( error ) {
throw error;
}
}
var fcns = [ foo, bar ];
waterfall( fcns, done );
```
To set the `this` context for **all** `functions` in the provided function array, provide a `thisArg`.
```javascript
function foo( next ) {
this.idx = 0;
next( null, 'beep' );
}
function bar( str, next ) {
this.idx += 1;
console.log( str );
// => 'beep'
next();
}
function done( error ) {
if ( error ) {
throw error;
}
console.log( ctx.idx );
// => 1
}
var ctx = {};
var fcns = [ foo, bar ];
waterfall( fcns, done, ctx );
```
#### waterfall.factory( fcns, done\[, thisArg] )
Returns a reusable waterfall `function`.
```javascript
function foo( next ) {
next( null, 'beep' );
}
function bar( str, next ) {
console.log( str );
// => 'beep'
next();
}
function done( error ) {
if ( error ) {
throw error;
}
}
var fcns = [ foo, bar ];
var run = waterfall.factory( fcns, done );
run();
run();
run();
```
## Notes
- The last argument applied to each waterfall `function` is a callback. The callback should be invoked upon a series `function` completion. The first argument is reserved as an `error` argument (which can be `null`). Any results which should be passed to the next `function` in the series should be provided beginning with the second argument.
- If any `function` calls the provided callback with a truthy `error` argument, the waterfall suspends execution and immediately calls the `done` callback for subsequent `error` handling.
- This implementation does **not** guarantee that execution is asynchronous. To do so, wrap the `done` callback in a `function` which either executes at the end of the current stack (e.g., `nextTick`) or during a subsequent turn of the event loop (e.g., `setImmediate`, `setTimeout`).
## Examples
```javascript
var replace = require( '@stdlib/string-replace' );
var waterfall = require( '@stdlib/utils-async-series-waterfall' );
function foo( next ) {
next( null, 'beep' );
}
function bar( str, next ) {
console.log( str );
next( null, replace( str, 'e', 'o' ) );
}
function fun( str, next ) {
console.log( str );
next();
}
function done( error ) {
if ( error ) {
throw error;
}
console.log( 'done' );
}
var fcns = [ foo, bar, fun ];
waterfall( fcns, done );
```
* * *
## Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/utils-async-series-waterfall.svg
[npm-url]: https://npmjs.org/package/@stdlib/utils-async-series-waterfall
[test-image]: https://github.com/stdlib-js/utils-async-series-waterfall/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/utils-async-series-waterfall/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/utils-async-series-waterfall/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/utils-async-series-waterfall?branch=main
[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/utils-async-series-waterfall/tree/deno
[deno-readme]: https://github.com/stdlib-js/utils-async-series-waterfall/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/utils-async-series-waterfall/tree/umd
[umd-readme]: https://github.com/stdlib-js/utils-async-series-waterfall/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/utils-async-series-waterfall/tree/esm
[esm-readme]: https://github.com/stdlib-js/utils-async-series-waterfall/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/utils-async-series-waterfall/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-async-series-waterfall/main/LICENSE