jxnblk/refunk

:headphones: Simple React functional setState

Refunk 🎧

Simple React functional setState with the new React context API (requires React v16.3 or later)

npm i refunk

Getting Started

import React from 'react'
import { connect } from 'refunk'

// Create a state provider component
const App = connect(props => (
  <div>
    <h1>count: {props.count}</h1>
    <Controls />
  </div>
))

// Updaters are functions that return state
const dec = state => ({ count: state.count - 1 })
const inc = state => ({ count: state.count + 1 })

// Connect the Controls component to the App state
const Controls = connect(props => (
  <div>
    <samp>{props.count}</samp>
    <button onClick={e => props.update(dec)}>
      -
    </button>
    <button onClick={e => props.update(inc)}>
      +
    </button>
  </div>
))

const initialState = {
  count: 0
}

// initialize state with props
render(<App {...initialState} />)

Usage

Refunk components initialize state from props and provide an update function to their consumers. When nesting Refunk components, the top-most component will control state for any child Refunk components.

The update function works the same as setState, but it's intended to be used with separate updater functions, that can be shared across many parts of an application.

connect

The connect higher-order component creates state based on props for top-level components or connects into a parent Refunk component's state when nested. This allows for the creation of stateful components that can work standalone or listen to a parent's state.

import React from 'react'
import { connect } from 'refunk'

const App = connect(props => (
  <div>
    <samp>{props.count}</samp>
  </div>
))

App.defaultProps = {
  count: 0
}

export default App

Provider

For lower-level access to React's context API, the Provider component can be used to create a context. The Refunk Provider will convert props to initial state and provide the state and update function through context.

import React from 'react'
import { Provider } from 'refunk'

const App = props => (
  <Provider count={0}>
    <div />
  </Provider>
)

Consumer

The context Consumer is also exported for lower-level access to the context API.

import React from 'react'
import { Provider, Consumer } from 'refunk'

const inc = state => ({ count: state.count + 1 })

const App = props => (
  <Provider count={0}>
    <Consumer>
      {state => (
        <React.Fragment>
          <samp>{state.count}</samp>
          <button onClick={e => state.update(inc)}>+</button>
        </React.Fragment>
      )}
    </Consumer>
  </Provider>
)

Using Updaters

Updaters are functions that are passed to the props.update() function. An updater function takes state as its only argument and returns a new state.

// updaters.js
// Create an `updaters` module with functions to update the state of the app
export const decrement = state => ({ count: state.count - 1 })
export const increment = state => ({ count: state.count + 1 })

// Counter.js
// Use the updater functions in the connected Counter component
import React from 'react'
import { connect } from 'refunk'
import { decrement, increment } from './updaters'

const Counter = props => (
  <div>
    <samp>Count: {props.count}</samp>
    <button onClick={e => props.update(decrement)}>
      Decrement
    </button>
    <button onClick={e => props.update(increment)}>
      Increment
    </button>
  </div>
)

export default connect(Counter)

// App.js
// Include the Counter component in App
import React from 'react'
import { connect } from 'refunk'
import Counter from './Counter'

const App = props => (
  <div>
    <h1>Hello</h1>
    <Counter />
  </div>
)

export default connect(App)

Build Your Own

Refunk's source is only about 50 LOC and relies on built-in React functionality. This library is intended to be used directly as a package and also to serve as an example of some ways to handle state in a React application. Feel free to fork or steal ideas from this project, and build your own version.

Concepts

Refunk is meant as a simpler, smaller alternative to other state managment libraries that makes use of React's built-in component state. Refunk uses higher-order components, the new context API, and React component state management along with functional setState to help promote the separation of presentational and container components, and to keep state updating logic outside of the components themselves.

This library also promotes keeping application state in a single location, similar to other Flux libraries and Redux.

Related

• microstate
• statty
• unistore
• redux
• unstated

---

Made by Jxnblk | MIT License

refunk's Issues

Failed context type: Parent provider detected

Hello,

I'm reaching an error when I want to use reunk from a parent component:

Warning: Failed context type: Parent provider detected in ``. Only one provider per app should be included.
    in Provider (at App.js:30)
    in div (created by Headroom)
    in div (created by Headroom)
    in Headroom (at App.js:29)
    in div (created by InstantSearch)
    in InstantSearch (created by CreateInstantSearch)
    in CreateInstantSearch (created by CreateInstantSearchServer)
    in CreateInstantSearchServer (at App.js:19)
    in Unknown (created by Provider)
    in Provider (at index.js?entry:61)
    in div (created by styled.div)
    in styled.div (created by Provider)
    in ThemeProvider (created by Provider)
    in Provider (at index.js?entry:60)
    in div (at Layout.js:14)
    in Unknown (at index.js?entry:59)
    in _class (created by Container)
    in AppContainer (created by Container)
    in Container (created by App)
    in div (created by App)
    in App

Any idea how to fix that?