https://github.com/slorber/rereduce

Reducer library for Redux
https://github.com/slorber/rereduce

Last synced: about 1 month ago
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Reducer library for Redux

• Host: GitHub
• URL: https://github.com/slorber/rereduce
• Owner: slorber
• License: mit
• Created: 2016-01-30T13:35:36.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2018-12-14T19:03:41.000Z (almost 6 years ago)
• Last Synced: 2024-04-23T19:39:01.641Z (8 months ago)
• Language: JavaScript
• Homepage: https://sebastienlorber.com/
• Size: 17.6 KB
• Stars: 164
• Watchers: 10
• Forks: 5
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-redux - rereduce - Reducer library for Redux. (Utilities)

README

        
# Rereduce

Simple reducer library for Redux. It's like Reselect but for reducers. 

By using aggressive memoization, reducers can depend on each others in an efficient way, without having to query Redux store.

It works fine with time-travel debugging and server-side rendering, because reducers remains totally stateless pure functions.

It permits to replace the imperative `waitFor` of original Flux implementation by a purely functional approach.

# API

The API is a first draft and may change in the future. Don't hesitate to discuss what the API should look like here: https://github.com/slorber/rereduce/issues/1

`createReducer( [reducerDependencies], reducerFunction)`

`[reducerDependencies]` is an optional object that looks like `{key1: reducer1, key2: reducer2}`

If dependencies are provided, `reducerFunction` will be called with a 3rd argument with the state of the dependency reducers.

### Simple Reducers (without dependencies)

Rereduce only add basic memoization on the original reducer.

You don't need to use `rereduce` for those reducers at all. But if you plan to make other reducers depend on your simple reducer, wrapping it with `rereduce` will be more CPU and memory efficient.

### Reducers with dependencies

- `reducerFunction` will be called with a 3rd argument with the state of the dependency reducers.

- The reducer always return an object with 2 attributes `value` and `__dependencies`

- `value` is the computed value of your reducing function.

- `__dependencies` is an attribute that you could simply ignore (don't worry, it does not consume as much additional memory as you may naively think).

- `__dependencies` is required to keep the reducer stateless.

- You should take care of the `__dependencies` attribute if you need efficient Redux store serialization/deserialization.

# Example

```javascript

import {  createReducer  } from 'rereduce'

const firstReducer =  createReducer((state = 0, action) => {

  switch (action.type) {

    case 'increment': return state + 1

    case 'decrement': return state - 1

    default: return state

  }

})

const secondReducer = createReducer({ firstReducer },

  (state = 0,action,{ firstReducer }) => firstReducer + 1

)

const rootReducer = combineReducers({ firstReducer, secondReducer })

const initialState = undefined

const stateInitialized = rootReducer(initialState,{ type: 'init' })

const stateIncremented = rootReducer(stateInitialized,{ type: 'increment' })

assert.equal(stateInitialized.firstReducer, 0)

assert.equal(stateInitialized.secondReducer.value, 1)

assert.equal(stateIncremented.firstReducer, 1)

assert.equal(stateIncremented.secondReducer.value, 2)

```

# Hire a freelance expert

Looking for a React/ReactNative freelance expert with more than 5 years production experience?

Contact me from my [website](https://sebastienlorber.com/) or with [Twitter](https://twitter.com/sebastienlorber).