Wondering what’s next for npm?Check out our public roadmap! »


    1.6.23 • Public • Published



    a shallow river in northeastern Italy, just south of Ravenna

    Node.js CI codecov npm version License: MIT Gitter

    [a]synchronous functional programming

    const { pipe, map, filter } = rubico
    const isOdd = number => number % 2 == 1
    const asyncSquare = async number => number ** 2
    const squaredOdds = pipe([
    squaredOdds([1, 2, 3, 4, 5]).then(console.log) // [1, 9, 25]


    Core build (~7.0 kB minified and gzipped)

    with npm

    npm i rubico

    require rubico in Node.js

    const rubico = require('rubico')
    const pipe = require('rubico/pipe')
    const tap = require('rubico/tap')
    const defaultsDeep = require('rubico/x/defaultsDeep')

    import rubico globally

    <!-- development -->
    <script src="https://unpkg.com/rubico"></script>
    <script src="https://unpkg.com/rubico/dist/pipe.js"></script>
    <script src="https://unpkg.com/rubico/dist/tap.js"></script>
    <script src="https://unpkg.com/rubico/dist/x/defaultsDeep.js"></script>
    console.log(rubico) // { pipe, tap, ... }
    console.log(pipe) // [Function: pipe]
    console.log(tap) // [Function: tap]
    console.log(defaultsDeep) // [Function: defaultsDeep]
    <!-- production -->
    <script src="https://unpkg.com/rubico/dist/rubico.min.js"></script>
    <script src="https://unpkg.com/rubico/dist/pipe.min.js"></script>
    <script src="https://unpkg.com/rubico/dist/tap.min.js"></script>
    <script src="https://unpkg.com/rubico/dist/x/defaultsDeep.min.js"></script>
    console.log(rubico) // { pipe, tap, ... }
    console.log(pipe) // [Function: pipe]
    console.log(tap) // [Function: tap]
    console.log(defaultsDeep) // [Function: defaultsDeep]

    import rubico via ES (JavaScript) Modules

    // development
    import rubico from 'https://unpkg.com/rubico/es.js'
    import pipe from 'https://unpkg.com/rubico/dist/pipe.es.js'
    import tap from 'https://unpkg.com/rubico/dist/tap.es.js'
    import defaultsDeep from 'https://unpkg.com/rubico/dist/x/defaultsDeep.es.js'
    // production
    import rubico from 'https://unpkg.com/rubico/dist/rubico.es.min.js'
    import pipe from 'https://unpkg.com/rubico/dist/pipe.es.min.js'
    import tap from 'https://unpkg.com/rubico/dist/tap.es.min.js'
    import defaultsDeep from 'https://unpkg.com/rubico/dist/x/defaultsDeep.es.min.js'


    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.


    Rubico is a module of twenty-eight operators for async-enabled functional programming in JavaScript.

    const {
      pipe, tap,
      switchCase, tryCatch,
      fork, assign, get, pick, omit,
      map, filter, reduce, transform, flatMap,
      and, or, not, any, all,
      eq, gt, lt, gte, lte,
      thunkify, always,
      curry, __,
    } = rubico

    These operators act sensibly on a wide range of vanilla JavaScript types to create declarative, extensible, and async-enabled function compositions.

    const { pipe, map } = rubico
    const toTodosUrl = id => `https://jsonplaceholder.typicode.com/todos/${id}`
    const logTodoByID = pipe([ // fetch a Todo and log it
      response => response.json(),
    const todoIDs = [1, 2, 3, 4, 5]
    map(logTodoByID)(todoIDs) // fetch Todos per id of TodoIDs and log them
    // { 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 }

    For different but semanticaly related functionality, Rubico exposes additional methods as property functions. For example,

    • map - apply a mapper function concurrently
    • map.pool - apply a mapper function concurrently with a concurrency limit
    • map.series - apply a mapper function serially

    For advanced functions, please visit rubico/x. You can find the full method documentation at rubico.land/docs.

    Awesome Resources


    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 announce on the issue thread that you will work on it.

    Pull requests should provide some basic context and link the relevant issue. Here is an example pull request. If you are interested in contributing, the help wanted tag is a good place to start.


    Rubico is MIT Licensed.


    • minimum Node.js version: 10.3
    • minimum Chrome version: 63
    • minimum Firefox version: 57
    • minimum Edge version: 79
    • minimum Safari version: 11.1


    npm i rubico

    DownloadsWeekly Downloads






    Unpacked Size

    1.97 MB

    Total Files




    Last publish


    • avatar