Ramduck Redux

Tired of creating reducers that aren't curried. Interested in partial application with Ramdajs ?

This little project brings the power of curry and composition (thanks to Ramda) into your redux project.

Previously

// reducer/user.js
export const INITIAL_STATE = {
  name: '',
  email: '',
};

// Actions types
export const CHANGE_NAME = 'change user name';
export const CHANGE_EMAIL = 'change user email';
export const CHANGE_USER = 'change user';

// Actions creator
export const changeName = name => ({ type: CHANGE_NAME, name });
export const changeEmail = email => ({ type: CHANGE_EMAIL, email });
export const changeUser = (name, email) => ({ type: CHANGE_USER, name, email });

// Reducer:
export default function (state = INITIAL_STATE, action) {
  switch(action.type) {
    case CHANGE_NAME:
      return {
        ...state,
        name: action.name,
      };
    case CHANGE_EMAIL:
      return  {
        ...state,
        email: action.email,
      };
    case CHANGE_USER:
      return {
        ...state,
        name: action.name,
        email: action.email,
      };
    default:
      return state;
  }
}

With Ramduck Redux

// reducer/user.js
import { action1, action2, createReducer, init, when, mergeAction } from 'ramduck-redux'
import { objOf, always, evolve, o, merge } from 'ramda'

export const initialState = {
  name: '',
  email: '',
};

// Actions creator
export const changeName = action1('change user name', name => { name });
// with obj of
export const changeEmail = action1('change user email', objOf('email'));
// with 2 arguments
export const changeUser = action2('change user', name => email => ({ name, email }))

// no need of action type, use your function as a string in order
// to retrieve the type:
// `${changeName}` === 'change user name'

// Reducer:
export default createReducer('user', [ // you must name it (handy with ramduck-react-redux)
  init(initialState),

  when(changeName, ({ name }) => state => ({
    ...state,
    name,
  })),

  // with evolve:
  when(changeEmail, ({ email }) => evolve({
    email: always(email),
  })),

  // with omit, merge and composition:
  when(changeUser, ({ name, email }) => state => ({
      ..state,
      name,
      email,
  })),

  // or with mergeAction (same behavior, it merge the action payload by removing
  // the type properties):
  // when(changeUser, mergeAction),
])


// In your main state file: reducer/index.js

import User from './user'
import { createRootReducer } from 'ramduck-redux'

// you can combine
// your reducers easily with:
const rootReducer = createRootReducer([ User ])

// your state will take the reducer name declare above and put it into a global
// state object of the shape:
// { user: <the user state> }

Installation

With npm:

npm i --save ramduck-redux

Or with yarn:

yarn add ramduck-redux

Usage

Actions

You can easily create curried action creator with the function action, action1, action2, action3, action4, actionN:

import { action, action1, action2, action3, action4 } from 'ramduck-redux'
import { objOf } from 'ramda'

// action with no parameter, only a type
const initialize = action('INITIALIZE');
// action with 1 parameter
const changeName = action1('CHANGE_NAME', objOf('name'))
// action with 2 parameter
const changeUser = action2('CHANGE_USER', name => email => ({ name, email }))
// same thing for action2, action3, action4 :)

// you can also create actions of N arguments with actionN
// const veryHugeAction = actionN(8, 'some type', a => b => c => e => f => g => h => i => ...)

// and then:
myAction() // { type: 'MY_TYPE' }
changeName('John') // { type: 'CHANGE_NAME', name: 'John' }
changeUser('John', '[email protected]') // { type: 'CHANGE_USER', name: 'John', email: '[email protected]' }

// action creators are curried:
const changeJohnEmail = changeUser('John'); // [Function]
const action = changeJohnEmail('[email protected]'); // { type: 'CHANGE_USER', name: 'John', email: '[email protected]' }

// no need of action types. You can access to the type be converting your
// action creator to string
`${changeUser}` === 'CHANGE_USER' // true

Reducer

You can create reducers much more easily with combine, init, when:

import { createReducer, createRootReducer, init, when } from 'ramduck-redux'

const simpleReducer = init({ name: 'John' });

simpleReducer(null, { type: 'some action' }); // { name: 'John' }
simpleReducer({ name: 'Jane' }, { type: 'some action' }); // { name: 'Jane' }

const changeNameReducer = when(
  'changeName',
  action => state => ({
    ...state,
    name: action.name,
  })
)

changeNameReducer({}, { type: 'changeName', name: 'john' }); // { name: 'john' }

// you can easily combine those methods to create much more complex
// reducers:
const reducer = createReducer('myReducerName', [
  init(myInitialState),

  when('SOME_TYPE', someTypeReducer),
  when('SOME_OTHER_TYPE', someOtherTypeReducer),
  when(['A', 'B'], somePluralActionReducer),
])

API Reference

data EmptyAction ::
  { type :: String
  }

data Action a ::
  { type :: String
  | a
  }

--| Actions helpers

action :: String -> () -> EmptyAction

actionN :: Number -> String -> (* -> a) -> * -> Action a

action1 :: String -> (a -> b) -> a -> Action b

action2 :: String -> (a -> b -> c) -> a -> b -> Action c

action3 :: String -> (a -> b -> c -> d) -> a -> b -> c -> Action d

action4 :: String -> (a -> b -> c -> d -> e) -> a -> b -> c -> d -> Action e

mergeAction :: Action a -> Object b -> Action { | a | b }


--| Reducers helpers

init :: a -> (Action b, a) -> a

whenAction :: String -> (Action a -> b -> b) -> (b, Action a) -> b

whenActions :: [String] -> (Action a -> b -> b) -> (b, Action a) -> b

when :: String|[String] -> (Action a -> b -> b) -> (b, Action a) -> b

createReducer :: String -> [((b -> Action a) -> b)] -> b -> Action a -> b

createRootReducer :: [((b -> Action a) -> b)] -> b -> Action a -> b