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A zero-runtime functional programming babel macro.

fp.macro This is a build-time functional programming library that allows you to use high-level collection functions without a production dependency and without the runtime penalty that you have when using a dedicated library.

It does so by exposing a Babel macro that is evaluated at build time by babel-plugin-macros. So in the end you do not have a production dependency anymore, it's all in the generated Babel code.


# npm
$ npm install fp.macro

# Yarn
$ yarn add fp.macro


Install babel-plugin-macros:

$ npm install babel-plugin-macros

The plugin is best used with the Babel pipeline operator, so optionally install this one as well:

$ npm install @babel/plugin-proposal-pipeline-operator

Then add the plugins to your babel config or create a .babelrc.json file:

  "plugins": [
    ["@babel/plugin-proposal-pipeline-operator", { "proposal": "fsharp" }]

Create a JavaScript file and start mapping collections:

import { filter, join, map, mapValues } from 'fp.macro'

const myMap = map(x => x * 2)

console.log(myMap([1, 2]))
// [2, 4]

// Using pipeline operator
  [1, 2, 3]
    |> map(x => x * 2)
    |> filter(x => x > 2)
    |> join(',')
// 4,6

  { foo: { name: 'foo' }, bar: { name: 'bar' } }
    |> mapValues(x => x.name)
// { foo: 'foo', bar: 'bar' }

To run the files, you need to use Babel. You can either compile them using @babel/cli, or run them directly via @babel/node (which is not recommended for production though).

The library is currently in development, so for more insights into the available functions check out the source code.


Are you missing something or want to contribute? Feel free to file an issue or a pull request! ⚙️


Hey, I am Sebastian Landwehr, a freelance web developer, and I love developing web apps and open source packages. If you want to support me so that I can keep packages up to date and build more helpful tools, you can donate here:

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Thanks a lot for your support! ❤️


MIT License © Sebastian Landwehr

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