Functional reactive programming for JavaScript and CoffeeScript.

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Fairmont is a family of JavaScript libraries for functional reactive programming. Fairmont takes full advantage of ES6+ features like iterators (including async iterators), generators, and promises. Inspired by libraries like Underscore and many others, Fairmont features include:
  • reactive programming support through async iterators
  • lazy evaluation on collection operations via iterators
  • core functional operations, like currying and composition
  • bridge functions for integrating with OOP-based libraries
  • common file and stream based operations
  • streams and event emitters modeled as asynchronous iterators
  • observers for reacting to changes in state
  • unifies synchronous and asynchronous programming models


Here's a simple reactive Web app implementing a counter using Fairmont's Reactive programming functions.
In JavaScript:
var $ = require("jquery"),
  F = require("fairmont");

$(function() {

  var data = { counter: 0 };

    F.events("click", $("a[href='#increment']")),
    F.map(function() { data.counter++; })

    F.events("change", F.observe(data)),
    F.map(function() {

In CoffeeScript:
{start, flow, events, map, observe} = require "fairmont-reactive"

$ = require "jquery"

$ ->

  data = counter: 0

  go [
    events "click", $("a[href='#increment']")
    map -> data.counter++

  go [
    events "change", observe data
    map ->
      .html data.counter

You can run this example or look at our other reactive examples:


You can simply install Fairmont as a whole:
npm install fairmont
Or you can simply install the components you need.
npm install fairmont-core
Learn more about the individual Fairmont components by clicking on the links below:

The API Reference provides documentation on each component and its corresponding functions.


Fairmont is available for production use. We use Fairmont is wide-variety of development projects. We welcome contributors!


You can get an idea of what we're planning by looking at the tickets. If you want something that isn't there, and you think it would be a good addition, please open a ticket.