https://github.com/richytong/rubico
[A]synchronous Functional Programming
https://github.com/richytong/rubico
async async-await asynchronous combinators concurrent function-composition functional-programming generator iterator javascript monad mux node operator parallel pointfree promise series tacit transducers
Last synced: about 2 months ago
JSON representation
[A]synchronous Functional Programming
- Host: GitHub
- URL: https://github.com/richytong/rubico
- Owner: a-synchronous
- License: mit
- Created: 2019-11-03T09:20:01.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2025-07-05T12:13:09.000Z (3 months ago)
- Last Synced: 2025-08-06T09:07:23.732Z (2 months ago)
- Topics: async, async-await, asynchronous, combinators, concurrent, function-composition, functional-programming, generator, iterator, javascript, monad, mux, node, operator, parallel, pointfree, promise, series, tacit, transducers
- Language: JavaScript
- Homepage: https://rubico.land
- Size: 4.42 MB
- Stars: 282
- Watchers: 11
- Forks: 16
- Open Issues: 56
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
Awesome Lists containing this project
- awesome-deno - rubico - 🏞 [a]synchronous function composition; it just works. (Modules / Utils)
README
# [rubico](https://rubico.land/)
> a shallow river in northeastern Italy, just south of Ravenna
[](https://codecov.io/gh/a-synchronous/rubico)
[](https://www.npmjs.com/package/rubico)
[](https://opensource.org/licenses/MIT)
## [A]synchronous Functional Programming
```javascript [playground]
const { pipe, map, filter } = rubico
const isOdd = number => number % 2 == 1
const asyncSquare = async number => number ** 2
const numbers = [1, 2, 3, 4, 5]
pipe(numbers, [
filter(isOdd),
map(asyncSquare),
console.log, // [1, 9, 25]
])
```
## Installation
[Core build](https://unpkg.com/rubico/index.js) ([~7.7 kB minified and gzipped](https://unpkg.com/rubico/dist/rubico.min.js)) [Transducer module](https://unpkg.com/rubico/dist/Transducer.js) ([~1.5kb minified and gzipped](https://unpkg.com/rubico/dist/Transducer.min.js))
with [npm](https://docs.npmjs.com/downloading-and-installing-node-js-and-npm):
```bash
npm i rubico
```
require rubico in [CommonJS](https://nodejs.org/docs/latest/api/modules.html#modules-commonjs-modules):
```javascript
// import rubico core globally
require('rubico/global')
// import rubico core as rubico
const rubico = require('rubico')
// import an operator from rubico core
const pipe = require('rubico/pipe')
// import rubico/x as x
const x = require('rubico/x')
// import an operator from rubico/x
const defaultsDeep = require('rubico/x/defaultsDeep')
// import rubico's Transducer module
const Transducer = require('rubico/Transducer')
```
import rubico in the browser:
```html [htmlmixed]
```
## Motivation
A note from the author
> At a certain point in my career, I grew frustrated with the entanglement of my own code. While looking for something better, I found functional programming. I was excited by the idea of functional composition, but disillusioned by the redundancy of effectful types. I started rubico to capitalize on the prior while rebuking the latter. Many iterations since then, the library has grown into something I personally enjoy using, and continue to use to this day.
rubico is founded on the following principles:
* asynchronous code should be simple
* functional style should not care about async
* functional transformations should be composable, performant, and simple to express
When you import this library, you obtain the freedom that comes from having those three points fulfilled. The result is something you may enjoy.
## Introduction
rubico is a library for [A]synchronous Functional Programming in JavaScript. The library supports a simple and composable functional style in asynchronous environments.
```javascript
const {
// compose functions
pipe, compose, tap,
// control flow
switchCase,
// handle errors
tryCatch,
// compose data
all, assign, get, set, pick, omit,
// iterate
forEach,
// transform data
map, filter, reduce, transform, flatMap,
// compose predicates
and, or, not, some, every,
// comparison operators
eq, gt, lt, gte, lte,
// partial application
thunkify, always, curry, __,
} = rubico
```
With [A]synchronous Functional Programming, any function may be asynchronous and return a promise. All promises are resolved for their values before continuing with the operation.
```javascript [playground]
const helloPromise = Promise.resolve('hello')
pipe(helloPromise, [ // helloPromise is resolved for 'hello'
async greeting => `${greeting} world`,
// the Promise returned from the async function is resolved
// and the resolved value is passed to console.log
console.log, // hello world
])
```
All rubico operators support both eager and lazy APIs. The eager API takes all required arguments and executes at once, while the lazy API takes only the setup arguments and returns a function that executes later. This dual API supports a natural and composable code style.
```javascript [playground]
const myObj = { a: 1, b: 2, c: 3 }
// the first use of map is eager
const myDuplicatedSquaredObject = map(myObj, pipe([
number => [number, number],
// the second use of map is lazy
map(number => number ** 2),
]))
console.log(myDuplicatedSquaredObject)
// { a: [1, 1], b: [4, 4], c: [9, 9] }
```
The rubico operators are versatile and act on a wide range of vanilla JavaScript types to create declarative, extensible, and async-enabled function compositions. The same operator `map` can act on an array and also a `Map` data structure.
```javascript [playground]
const { pipe, tap, map, filter } = rubico
const toTodosUrl = id => `https://jsonplaceholder.typicode.com/todos/${id}`
const todoIDs = [1, 2, 3, 4, 5]
pipe(todoIDs, [
// fetch todos per id of todoIDs
map(pipe([
toTodosUrl,
fetch,
response => response.json(),
tap(console.log),
// { userId: 1, id: 4, title: 'et porro tempora', completed: true }
// { userId: 1, id: 1, title: 'delectus aut autem', completed: false }
// { userId: 1, id: 3, title: 'fugiat veniam minus', completed: false }
// { userId: 1, id: 2, title: 'quis ut nam facilis...', completed: false }
// { userId: 1, id: 5, title: 'laboriosam mollitia...', completed: false }
])),
// group the todos by userId in a new Map
function createUserTodosMap(todos) {
const userTodosMap = new Map()
for (const todo of todos) {
const { userId } = todo
if (userTodosMap.has(userId)) {
userTodosMap.get(userId).push(todo)
} else {
userTodosMap.set(userId, [todo])
}
}
return userTodosMap
},
// filter for completed todos
// map iterates through each value (array of todos) of the userTodosMap
// filter iterates through each todo of the arrays of todos
map(filter(function didComplete(todo) {
return todo.completed
})),
tap(console.log),
// Map(1) {
// 1 => [ { userId: 1, id: 4, title: 'et porro tempora', completed: true } ]
// }
])
```
rubico offers transducers through its `Transducer` module. You can consume these transducers with rubico's `transform` and `compose` operators. You can use `compose` to chain a left-to-right composition of transducers.
```javascript [playground]
const isOdd = number => number % 2 == 1
const asyncSquare = async number => number ** 2
const generateNumbers = function* () {
yield 1
yield 2
yield 3
yield 4
yield 5
}
pipe(generateNumbers(), [
transform(compose(
Transducer.filter(isOdd),
Transducer.map(asyncSquare),
), []),
console.log, // [1, 9, 25]
])
```
For advanced asynchronous use cases, some of the rubico operators have property functions that have various asynchronous behavior, e.g.
* `map` - applies a mapper function concurrently
* `map.pool` - applies a mapper function concurrently with a concurrency limit
* `map.series` - applies a mapper function serially
For more functions beyond the core operators, please visit `rubico/x`. You can find the full documentation at [rubico.land/docs](https://rubico.land/docs).
## Benchmarks
Please find the published benchmark output inside the [benchmark-output](https://github.com/a-synchronous/rubico/tree/master/benchmark-output) folder. You can run the benchmarks on your own system with the following command:
```
npm run bench
```
## Contributing
Your feedback and contributions are welcome. If you have a suggestion, please raise an issue. Prior to that, please search through the issues first in case your suggestion has been made already. If you decide to work on an issue, please create a pull request.
Pull requests should provide some basic context and link the relevant issue. Here is an [example pull request](https://github.com/a-synchronous/rubico/pull/12). If you are interested in contributing, the [help wanted](https://github.com/a-synchronous/rubico/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22) tag is a good place to start.
For more information please see [CONTRIBUTING.md](/CONTRIBUTING.md)
## License
rubico is [MIT Licensed](https://github.com/a-synchronous/rubico/blob/master/LICENSE).
## Support
* minimum Node.js version: 16
* minimum Chrome version: 63
* minimum Firefox version: 57
* minimum Edge version: 79
* minimum Safari version: 11.1
## Blog
Learn more about rubico and [A]synchronous Functional Programming at [https://rubico.land/blog](https://rubico.land/blog).