bcherny/redrock

Typesafe, reactive redux

Highlights

• 100% type-safe:
  • Statically guarantees that a reducer is defined for each Action
  • Statically guarantees that emitters are called with the correct Action data given their Action name
  • Statically guarantees that listeners are called with the correct Action data given their Action name
• Mental model similar to Redux, with several improvements over Redux:
  • Store is decoupled from emitter
  • Emitters are reactive; in fact, they use Rx Observables!
  • Listeners are on specific Actions
  • Listeners are called with both current and previous values (convenience borrowed from Angular $watch/Object.Observe)

Conceptual Overview

1. Create a redrock Emitter with a set of supported Actions
2. Register reducers on the emitter (a "reducer" is a mapping from a given Action to its side effects)
3. Components in your app emit() Actions on your emitter
4. Actions first trigger side-effects (via their respective reducers), then trigger any callbacks listening on that Action (callbacks are registered with on())

Installation

npm install redrock --save

Usage

import { Emitter } from 'redrock'

// Mock store
const store: { [id: number]: boolean } = {}

// Enumerate actions
type Actions = {
  INCREMENT_COUNTER: number
  OPEN_MODAL: boolean
}

// Define redrock Emitter
class App extends Emitter<Actions> { }

// Create bus and register reducers (throws a compile time error unless both of these keys are defined, and return values of the right types)
const app = new App({
  INCREMENT_COUNTER: ({ id, value }) => {
    const previousValue = store[id]
    store[id] = value
    return previousValue
  },
  OPEN_MODAL: ({ id, value }) => {
    const previousValue = store[id]
    store[id] = value
    return previousValue
  }
})

// Listen on an action (throws a compile time error if this event does not exist) (basic)
app.on('OPEN_MODAL')
   .subscribe(_ => _.value)

// Listen on an action (advanced)
app.on('INCREMENT_COUNTER')
   .filter(_ => _.id === 42)
   .debounce()
   .subscribe(_ => console.log(`Counter incremented from ${_.previousValue} to ${_.value}!`))

// Trigger an action (throws a compile time error unless id and value are set, and are of the right types)
app.emit('OPEN_MODAL', { id: 123, value: true })

Tests

npm test