redux-map-action

Higher-order Redux reducer to map actions before passing to a reducer.

Usage

Install via NPM

npm install redux-map-action --save

Import

import mapAction from 'redux-map-action';
// or
var mapAction = require('redux-map-action');

If you need ES6 module

import mapAction from 'redux-map-action/es6';

Use this if you are using rollup.js or webpack 2, or any ES2015 modules-compatible bundler which can eliminate unused library code with tree-shaking.

It is recommended to import the library from redux-map-action/es6 instead of redux-map-action/src because the source code depends on experimental presets from babel (stage 1-3) and may be incompatible with your bundler or settings.

Other environments

Use the Universal Module Definition (UMD)

• mapState.js
• mapState.min.js (minified)

API

mapAction()

 mapAction(
   actionMapper: (action: Object) => newAction: Object,
   actionTypes: ?Array<string>
 ): (reducer) => reducer

Creates a higher-order reducer which map actions before passing to a reducer. Specify a list of action types to whitelist actions for mapping.

Useful when you want reuse a reducer on actions with different payloads.

Example

Lets say we have a itemListReducer which handles the state for a list of items, and we want to store items with different priorities in separate lists. In this case we can use mapAction() to filter items in actions by priority before passing to respective reducers.

./items-reducer.js

import { combineReducers } from 'redux';
import mapAction from 'redux-map-action';
import itemListReudcer from './item-list-reducer';
import { FETCH, UPDATE } from './constants/action-types';
import { URGENT, NORMAL } from './constants/priority';

const mapPriority = (priority) => mapAction(
  (action) => ({
    ...action,
    payload: action.payload.filter((item) => item.priority === priority)
  }),
  [FETCH, UPDATE]
);

const itemsReducer = combineReducers({
  urgent: mapPriority(URGENT)(itemListReducer),
  normal: mapPriority(NORMAL)(itemListReducer),
});

export default itemsReducer;