assign-reducers

Combine Redux reducer functions much like Object.assign.

Installation

Via npm

npm i --save @haensl/assign-reducers

Via yarn

yarn add @haensl/assign-reducers

Usage

ESM

import assignReducers from '@haensl/assign-reducers';
import { createStore } from 'redux';

// ...

const rootReducer = assignReducers(someReducer, {
  subTree: someOtherReducer
});
const store = createStore(
  rootReducer,
  initialState
);

CommonJS

const assignReducers = require('@haensl/assign-reducers');
const { createStore } = require('redux');
// ...

const rootReducer = assignReducers(someReducer, {
  subTree: someOtherReducer
});

const store = createStore(
  rootReducer,
  initialState
);

Example

import assignReducers from '@haensl/assign-reducers';
import actions from './actions';
import anotherReducer from 'somewhere/else/in/my/project/reducer';

const initialState = {
  value: 1
};

const reducer = (state = initialState, action) => {
  switch (action.type) {
    case actions.ADD:
      return {
        ...state,
        value: state.value + 1
      };
    default:
      return state;
  }
};

export default assignReducers(
  reducer,
  {
    foo: anotherReducer
  }
);

// Resulting state:
// {
//    value: 1,
//    foo: initial state returned by anotherReducer
// }

Synopsis

assignReducers(reducer, reducersObject) => reducer

assignReducers combines reducers analogous to Object.assign, i.e. with a shallow merge.

Parameters

reducer

A regular Redux reducer function which forms the base of the state (sub-) tree object.

Example

const reducer = (state = initialState, action) => {
  switch (action.type) {
    case actions.DO_SOMETHING:
      return {
        // changed state
      };
    default:
      return state;
  }
};

recudersObject

An object mappging keys to Redux reducer functions. The keys will me merged shallowly into the state created by reducer.

Example

const reducersObject = {
  foo: reducerB,
  bar: reducerC
};

const newReducer = assignReducers(reducerA, reducersObject);
// state returned by newReducer:
// {
//    foo: state returned by reducerB,
//    bar: state returned by reducerC,
//    state returned by reducerA
// }

FAQ

• Does assignReducers() work with combineReducers()?

  Yes, it does. Since all we need are reducer functions you can combine the two in any way you like. You can for example do stuff like

  assignReducers(
    reducerA,
    {
      foo: combineReducers({
        bar: reducerB,
        baz: reducerC
      })
    }
  );`

Changelog

License

MIT