@duckness/pool NPM

`@duckness/pool`

Example

import Pool from '@duckness/pool'
import CounterDuck from './ducks/CounterDuck'

const CounterPool = Pool({
  buildStore: ({ initialCounter = 0 } = {}) => {
    return { counter: initialCounter }
  }
})
CounterPool.addDuck(CounterDuck)

CounterPool.build({initialCounter: 0})
CounterPool.store
// => [redux store]

API

Create Pool

const myPool = Pool({
  ?poolName: String, // pool name, default is 'pool'
  ?ducks: Array<Duck>, // array of pool ducks
  ?middlewares: Array<Middleware>, // additional middlewares for Redux store
  ?streams: Array<PoolStream>, // pool plugins
  ?buildStore: (props, { refProps, refDucks, refErrorReporter }) => storeState, // build initial store state
  ?buildRootReducer: ({ refDucks, refErrorReporter }) => rootReducer // build custom root reducer from ducks instead of default root reducer
})

`buildStore`

Optional function to build init store state (props, { refProps, refDucks, refReducers, refErrorReporter }) => storeState

props are passed to pool when pool.build(props) are called.
refProps.current - props passed to pool.build(props) function
refDucks.current - current array of ducks.
refReducers.root - pool root reducer
refReducers.pre - pool pre reducer
refReducers.post - pool post reducer
refErrorReporter.current - current error reporter function.

default `buildStore`

If not specified store state will be set to {}.

`buildRootReducer`

Optional function for custom root reducer (ducks, { refProps, refDucks, refReducers, refErrorReporter }) => rootReducer

ducks - array of ducks
refProps.current - props passed to pool.build(props) function
refDucks.current - current array of ducks.
refReducers.pre - pool pre reducer
refReducers.post - pool post reducer
refErrorReporter.current - current error reporter function.

default `buildRootReducer`

Default root reducer will combine all duck root reducers via

ducks.reduce((state, duck) => {
  return duck(state, action)
}, state)

with every duck root reducer wrapped in try/catch returning unmodified state in case of exception inside duck root reducer.

`.addDuck(duck)`

Add duck to pool.

MyPool.addDuck(myDuck)

`.preReducer(reducer)`

Add pool pre reducer. Pre reducers will run BEFORE duck reducers and will receive all actions. Will replace previously set pre reducer.

MyPool.preReducer(function globalPreReducer(state, action) {/* ... */} )

`.postReducer(reducer)`

Add pool post reducer. Post reducers will run AFTER duck reducers and will receive all actions. Will replace previously set post reducer.

MyPool.postReducer(function globalPostReducer(state, action) {/* ... */} )

`.build(props)`

Build pool state from some props. props will be passed to buildStore function.

MyPool.build({ initialCounter: 0 })

`.store`

Reference to built redux store.

MyPool.store.subscribe(/* ... */)

`.dispatch(...)`

Dispatches an action (action is a plain object).

const action = { type: 'actionType', payload: {} }
MyPool.dispatch(action)

Dispatches and action from 'poolName/duckName' duck. This will first look for a duck by 'duckName' and current 'poolName', then duck's action creator by 'actionName' and call it with 'actionParams' to build action to dispatch.

MyPool.dispatch('duckName', 'actionName', ...actionParams)

Example:

const MyDuck = Duck('myDuck', 'myPool')
MyDuck.action('someAction')

const MyPool = Pool({ poolName: 'myPool' })
MyPool.addDuck(MyDuck)
MyPool.dispatch('myDuck', 'someAction', ...actionParams)

// equal to
MyPool.dispatch(MyDuck.action.someAction(...actionParams))

Dispatches and action from 'customPoolName/duckName' duck. This will first look for a duck by 'duckName' and 'poolName', then duck's action creator by 'actionName' and call it with 'actionParams' to build action to dispatch.

MyPool.dispatch(['customPoolName', 'duckName'], 'actionName', ...actionParams)

`.reduce([state,] action)`

Reduce state with action. Does not change pool's store. Can be used to look ahead what the state will be after dispatching an action.

MyPool.reduce(action) // reduce pool's store state
MyPool.reduce(state, action) // reduce custom state

`.select(?selector)`

Select something from store. Returns store state if selector undefined.

MyPool.select(MyDuck.select.something)
// => selected value
MyPool.select()
// => current store state

`.fetch(selector, ?resolver)`

Returns Promise

function resolver(selected, resolve, prevSelected)

Fetch value from the store:

first selector is called to produce selected value
if resolver is defined: selected value is passed to resolver with previous selected value (undefined for the first run) and resolve function that can be used to resolve this fetch
if resolver is not defined: selected value will be resolved if it is not undefined
if nothing was resolved: repeat when store is updated (after next action dispatch).

fetch will subscribe to store updates (if it was not resolved after first select) and unsubscribe when it is resolved.

// resolves with items when items are loaded into store or are already present
const items = await ListPool.fetch(ItemsDuck.select.items)

// resolves when counter is reset, returning counter value before reset
const counterResetFrom = await MyPool.fetch(
  state => state.counter,
  (selected, resolve, prevSelected) => {
    if (null != prevSelected && 0 !== prevSelected && 0 === selected) {
      resolve(selected)
    }
  }
)

`.trigger(selector, callback, ?resolver)`

Returns clear trigger function.

function callback(selected)

function resolver(selected, resolve, prevSelected)

Trigger callback every time:

selected value changes (resolver is undefined)
or resolver calls resolve

trigger calls resolver first time trigger is set and later on store updates.

To unsubscribe call clear trigger function.

// console.log value for 10 seconds
const clearTrigger = MyPool.trigger(
    MyDuck.select.someValue,
    console.log
  )
setTimeout(clearTrigger, 10000)

`.setErrorReporter(reporterFn)`

Set exception reporter function. Will also overwrite errorReporters set in ducks.

MyPool.setErrorReporter(error => {
  window.Sentry.captureException(error)
})

`.reportError(error)`

Call assigned error reporter

MyPool.reportError(new Error('Clean pool!'))

`.addMiddleware(middleware)`

Add custom Redux middleware (applied on .build)

Pool Streams - Pool plugins

Pool Stream is a Pool plugin that can add middlewares to Redux store. One example is @duckness/pool-saga-stream that adds @duckness/saga support to Pool (ducks can have Redux Sagas).

`.addStream(poolStream)`

Adds Pool Stream to Pool

`PoolStream` API

{
  // array of middlewares for Redux store
  middlewares({ refDucks, refProps, refReducers, refErrorReporter }) {
    // refDucks.current - current array of ducks
    // refProps.current - props passed to build function
    // refReducers.root - root reducer function
    // refReducers.pre - pool pre reducer function
    // refReducers.post - pool post reducer function
    // refErrorReporter.current - current error reporter function
    // ...
    return [...streamMiddlewares] 
  },
  // called before redux store is built
  beforeBuild({ refDucks, refProps, refReducers, refErrorReporter }) {
    // refDucks.current - current array of ducks
    // refProps.current - props passed to build function
    // refReducers.root - root reducer function
    // refReducers.pre - pool pre reducer function
    // refReducers.post - pool post reducer function
    // refErrorReporter.current - current error reporter function
    // ...
  },
  // called after redux store is built
  afterBuild({ refStore, refDucks, refProps, refReducers, refErrorReporter }) {
    // refStore.current - current Redux store
    // refDucks.current - current array of ducks
    // refProps.current - props passed to build function
    // refReducers.root - root reducer function
    // refReducers.pre - pool pre reducer function
    // refReducers.post - pool post reducer function
    // refErrorReporter.current - current error reporter function
    // ...
  }
}