Babel Syntax Monadic For Support

This is a plugin for Babel 7 that is meant to replicate Scala's for comprehension or haskell's do syntax.

Babel >= 7.x

{
  "plugins": [
    "babel-plugin-syntax-monadic-comprehensions",
  ]
}

Installation & Usage

$ npm install --save-dev babel-plugin-syntax-monadic-comprehensions

Add the following line to your .babelrc file:

{
    "plugins": ["babel-plugin-syntax-monadic-comprehensions"]
}

This will transform this kind of code:

import Identity, { For, Yield } from './Identity'

const comp = For(() => {
    const a = Yield(Identity.pure(1))
    const b = Yield(Identity.pure(1))
    return a + b
})

// => Identity(2)

in this code:

import { flatMap, map } from "./Identity";
import Identity, { For, Yield } from './Identity';

const comp = flatMap(Identity.pure(1), a => {
    return map(Identity.pure(1), b => {
    return a + b;
    });
});

// => Identity(2)

Where Identity is the identity monad instance.

note Assumes that the module from which For and Yield are imported also export flatMap and map operators.

License

MIT (c) 2015