What's The Story?

Provides a few tools for working with Redux-based codebases.

Currently includes:

1. createReducer - declutter reducers for readability and testing
2. createTypes - DRY define your types object from a string
3. createActions - builds your Action Types and Action Creators at the same time
4. resettableReducer - allows your reducers to be reset

More coming soon...

createReducer

We're all familiar with the large switch statement and noise in our reducers, and because we all know this clutter, we can use createReducer to assume and clear it up! There are a few patterns I've learned (and was taught), but let's break down the parts of a reducer first:

1. Determining the initial state.
2. Running
3. Knowing when to run.
4. Injecting into the global state tree

Initial State

Every reducer I've written has a known and expected state. And it's always an object.

const INITIAL_STATE = { name: null, age: null }

If you're using seamless-immutable, this just get's wrapped. This is optional.

const INITIAL_STATE = Immutable({ name: null, age: null })

Running

A reducer is a function. It has 2 inbound parameters and returns the new state.

export const sayHello = (state = INITIAL_STATE, action) => {
  const { age, name } = action
  return { ...state, age, name }
}

Notice the export? That's only needed if you would like to write some tests for your reducer.

Knowing When To Run

In Redux, all reducers fire in response to any action. It's up to the reducer to determine if it should run in response. This is usually driven by a switch on action.type.

This works great until you start adding a bunch of code, so, I like to break out "routing" from "running" by registering reducers.

We can use a simple object registry to map action types to our reducer functions.

import Types from './actionTypes'

export const HANDLERS = {
  [Types.SAY_HELLO]: sayHello,
  [Types.SAY_GOODBYE]: sayGoodbye
}

The export is only needed for testing. It's optional.

Default handler

Sometimes you want to add a default handler to your reducers (such as delegating actions to sub reducers). To achieve that you can use DEFAULT action type in your configuration.

import Types from './actionTypes'
import { Types as ReduxSauceTypes } from 'reduxsauce'

export const HANDLERS = {
  [Types.SAY_GOODBYE]: sayGoodbye
  [Types.SAY_GOODBYE]: sayGoodbye
  [ReduxSauceTypes.DEFAULT]: defaultHandler,
}

With code above defaultHandler will be invoked in case the action didn't match any type in the configuration.

Injecting Into The Global State Tree

I like to keep this in the root reducer. Since reducers can't access other reducers (lies -- it can, but it's complicated), my preference is to not have the reducer file have an opinion.

I like to move that decision upstream. Up to the root reducer where you use Redux's combineReducers().

So, that brings us back to reduxsauce. Here's how we handle exporting the reducer from our file:

export default createReducer(INITIAL_STATE, HANDLERS)

That's it.

Complete Example

Here's a quick full example in action.

// sampleReducer.js
import { createReducer } from 'reduxsauce'
import Types from './actionTypes'

// the initial state of this reducer
export const INITIAL_STATE = { error: false, goodies: null }

// the eagle has landed
export const success = (state = INITIAL_STATE, action) => {
  return { ...state, error: false, goodies: action.goodies }
}

// uh oh
export const failure = (state = INITIAL_STATE, action) => {
  return { ...state, error: true, goodies: null }
}

// map our action types to our reducer functions
export const HANDLERS = {
  [Types.GOODS_SUCCESS]: success,
  [Types.GOODS_FAILURE]: failure
}

export default createReducer(INITIAL_STATE, HANDLERS)

This becomes much more readable, testable, and manageable when your reducers start to grow in complexity or volume.

createTypes

Use createTypes() to create the object representing your action types. It's whitespace friendly.

// Types.js
import { createTypes } from 'reduxsauce'

export default createTypes(`
  LOGIN_REQUEST
  LOGIN_SUCCESS
  LOGIN_FAILURE

  CHANGE_PASSWORD_REQUEST
  CHANGE_PASSWORD_SUCCESS
  CHANGE_PASSWORD_FAILURE

  LOGOUT
`, {}) // options - the 2nd parameter is optional

Options

• prefix: prepend the string to all created types. This is handy if you're looking to namespace your actions.

createActions

Use createActions() to build yourself an object which contains Types and Creators.

import { createActions } from 'reduxsauce'

const { Types, Creators } = createActions({
  loginRequest: ['username', 'password'],
  loginSuccess: ['username'],
  loginFailure: ['error'],
  requestWithDefaultValues: { username: 'guest', password: null }
  logout: null,
  custom: (a, b) => ({ type: 'CUSTOM', total: a + b })
}, {}) // options - the 2nd parameter is optional

The keys of the object will become keys of the Creators. They will also become the keys of the Types after being converted to SCREAMING_SNAKE_CASE.

The values will control the flavour of the action creator. When null is passed, an action creator will be made that only has the type. For example:

Creators.logout() // { type: 'LOGOUT' }

By passing an array of items, these become the parameters of the creator and are attached to the action.

Creators.loginRequest('steve', 'secret') // { type: 'LOGIN_REQUEST', username: 'steve', password: 'secret' }

By passing an object of { key: defaultValue }, default values are applied.

In this case, invoke the action by putting all parameters into an object as the first argument.

Creators.requestWithDefaultValues({
  password: '123456',
  undefinedKeyWontBeUsed: true
})
// { type: 'REQUEST_WITH_DEFAULT_VALUES', username: 'guest', password: '123456' }

Options

• prefix: prepend the string to all created types. This is handy if you're looking to namespace your actions.

resettableReducer

Provides a "higher-order reducer" to help reset your state. Instead of adding an additional reset command to your individual reducers, you can wrap them with this.

Check it out.

import { resettableReducer } from 'reduxsauce'
import { combineReducers } from 'redux'

// some reducers you have already created
import firstReducer from './firstReducer'
import secondReducer from './secondReducer'
import thirdReducer from './thirdReducer'

// listen for the action type of 'RESET', you can change this.
const resettable = resettableReducer('RESET')

// reducers 1 & 3 will be resettable, but 2 won't.
export default combineReducers({
  first: resettable(firstReducer),
  second: secondReducer,
  third: resettable(thirdReducer)
})

Changes

September 26, 2017 - 0.7.0

• NEW Adds ability to have a default or fallback reducer for nesting reducers or catch-alls. @vaukalak
• NEW Adds default values to createActions if passed an object instead of an array or function. @zhang-z
• DOCS Fixes typos. @quajo

July 10, 2017 - 0.6.0

• NEW Makes unbundled code available for all you tree-shakers out there. @skellock & @messense
• FIX Corrects issue with prefixed action names. @skellock
• FIX Upgrades dependencies. @messense

April 7, 2017 - 0.5.0

• NEW adds resettableReducer for easier reducer uh... resetting. @skellock

December 12, 2016 - 0.4.1

• FIX creators now get the prefix as well. @jbblanchet

December 8, 2016 - 0.4.0

• NEW createActions and createTypes now take optional options object with prefix key. @jbblanchet & @skellock

September 8, 2016 - 0.2.0

• NEW adds createActions for building your types & action creators. @gantman & @skellock

May 17, 2016 - 0.1.0

• NEW adds createTypes for clean type object creation. @skellock

May 17, 2016 - 0.0.3

• DEL removes the useless createAction function. @skellock

May 17, 2016 - 0.0.2

• FIX removes the babel node from package.json as it was breaking stuff upstream. @skellock

May 17, 2016 - 0.0.1

• NEW initial release. @skellock