Package Exports

redux-create-reducer

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (redux-create-reducer) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

redux-create-reducer

This code packaged as a node module

Usage:

import { createReducer } from 'redux-create-reducer';
import * as ActionTypes from '../constants/ActionTypes';

const initialState = [];

export const todos = createReducer(initialState, {
  [ActionTypes.ADD_TODO](state, action) {
    const text = action.text.trim();
    return [...state, text];
  },

  [ActionTypes.REMOVE_TODO](state, action) {
    return state.filter((_, i) => i !== action.index);
  }

  // All other action types result in state being returned
})

Typescript typings

This library also provides powerful typescript typings when using Action classes:

interface Action {
  type: string;
}

interface State {
  value: number;
}

class Reset implements Action {
  readonly type = 'Reset Action';
}
class AddOne implements Action {
  readonly type = 'AddOne Action';
}
class AddCustom implements Action {
  readonly type = 'AddCustom Action';
  constructor(public readonly value: number) { }
}

type Actions = Reset | AddOne | AddCustom;

const reducer = createReducer<State, Actions>({ value: 0 }, {
  'Reset Action': (state, action) => ({ value: 0 }),
  'AddOne Action': (state, action) => ({ value: state.value + 1 }),
  'AddCustom Action': (state, action) => ({ value: state.value + action.value }),
});

// If you wanted to exclude some actions you can use the `Exclude` type.
type ActionsWithoutAddOne = Exclude<Actions, AddOne>
const reducerThatDoesNotHandleAddOne = createReducer<State, ActionsWithoutAddOne>({ value: 0 }, {
  'Reset Action': (state, action) => ({ value: 0 }),
  'AddCustom Action': (state, action) => ({ value: state.value + action.value }),
});

Stackblitz

Removing 'Reset Action': (state, action) => ({ value: 0 }), in the reducer causes the error: Property '"Reset Action"' is missing in type .... Similarly, adding 'Nonexisting Action': (state, action) => ({ value: 0 }), causes the type error: Object literal may only specify known properties, and ''Nonexisting Action'' does not exist in type 'Handlers<State, Actions>'.ts(2345)