Reactive state manager
- Introduction
- Installation
- Press
- Online playground
- Examples
- API
- Tested with browserstack
- Contributors
- License
Effector is an effective multi store state manager for Javascript apps (React/React Native/Vue/Node.js), that allows you to manage data in complex applications without the risk of inflating the monolithic central store, with clear control flow, good type support and high capacity API. Effector supports both TypeScript and Flow type annotations out of the box.
- Application stores should be as light as possible - the idea of adding a store for specific needs should not be frightening or damaging to the developer.
- Application stores should be freely combined - data that the application needs can be statically distributed, showing how it will be converted in runtime.
- Autonomy from controversial concepts - no decorators, no need to use classes or proxies - this is not required to control the state of the application and therefore the api library uses only functions and simple js objects
- Predictability and clarity of API - A small number of basic principles are reused in different cases, reducing the user's workload and increasing recognition. For example, if you know how .watch works for events, you already know how .watch works for stores.
- The application is built from simple elements - space and way to take any required business logic out of the view, maximizing the simplicity of the components.
npm install --save effectorOr using yarn
yarn add effector-
For Web Framework/Libraries:
Package Version Dependencies effector-reacteffector-vue -
For another languages:
Package Version Dependencies bs-effectorbs-effector-react
- Why I choose Effector instead of Redux or MobX
- Effector — State Manager You Should Give a Try
- Powerful and fast 5kb state manager
You can try effector in our repl
Code sharing, Typescript and react supported out of the box; and of course, it built with effector
import {createStore, createEvent} from 'effector'
import {useStore} from 'effector-react'
const increment = createEvent('increment')
const decrement = createEvent('decrement')
const resetCounter = createEvent('reset counter')
const counter = createStore(0)
.on(increment, state => state + 1)
.on(decrement, state => state - 1)
.reset(resetCounter)
counter.watch(console.log)
const Counter = () => {
const value = useStore(counter)
return <div>{value}</div>
}
const App = () => {
const value = useStore(counter)
return (
<>
<Counter />
<button onClick={increment}>+</button>
<button onClick={decrement}>-</button>
<button onClick={resetCounter}>reset</button>
</>
)
}const {createEvent} = require('effector')
const messageEvent = createEvent()
messageEvent.watch(text => console.log(`new message: ${text}`))
messageEvent('hello world')
// => new message: hello worldconst {createStore, createEvent} = require('effector')
const turnOn = createEvent()
const turnOff = createEvent()
const status = createStore('offline')
.on(turnOn, () => 'online')
.on(turnOff, () => 'offline')
status.watch(newStatus => {
console.log(`status changed: ${newStatus}`)
})
// for store watchs callback invokes immediately
// "status changed: offline"
turnOff() // nothing has changed, callback is not triggered
turnOn() // "status changed: online"
turnOff() // "status changed: offline"
turnOff() // nothing has changedWith effects for data fetching and effector-react hooks
With useList hook
Basic example
Event is an intention to change state.
import {createEvent} from 'effector'
const send = createEvent() // unnamed event
const onMessage = createEvent('message') // named event
const socket = new WebSocket('wss://echo.websocket.org')
socket.onmessage = msg => onMessage(msg)
socket.onopen = () => send('{"text": "hello"}')
const onMessageParse = onMessage.map(msg => JSON.parse(msg.data))
onMessageParse.watch(data => {
console.log('Message from server ', data)
})
send.watch(data => {
socket.send(data)
})Effect is a container for async function. It can be safely used in place of the original async function.
import {createEffect} from 'effector'
const fetchUserRepos = createEffect({
async handler({name}) {
const url = `https://api.github.com/users/${name}/repos`
const req = await fetch(url)
return req.json()
},
})
// subscribe to pending store status
fetchUserRepos.pending.watch(pending => {
console.log(pending) // false
})
// subscribe to handler resolve
fetchUserRepos.done.watch(({params, result}) => {
console.log(params) // {name: 'zerobias'}
console.log(result) // resolved value
})
// subscribe to handler reject or throw error
fetchUserRepos.fail.watch(({params, error}) => {
console.error(params) // {name: 'zerobias'}
console.error(error) // rejected value
})
// subscribe to both cases
fetchUserRepos.finally.watch(data => {
if (data.status === 'done') {
const {params, result} = data
console.log(params) // {name: 'zerobias'}
console.log(result) // resolved value
} else {
const {params, error} = data
console.error(params) // {name: 'zerobias'}
console.error(error) // rejected value
}
})
// you can replace handler anytime
fetchUserRepos.use(requestMock)
// calling effect will return a promise
const result = await fetchUserRepos({name: 'zerobias'})Store is an object that holds the state tree. There can be multiple stores.
// `getUsers` - is an effect
// `addUser` - is an event
const defaultState = [{ name: Joe }];
const users = createStore(defaultState)
// subscribe store reducers to events
.on(getUsers.done, (oldState, payload) => payload)
.on(addUser, (oldState, payload) => [...oldState, payload]))
// subscribe side-effects
const callback = (newState) => console.log(newState)
users.watch(callback) // `.watch` for a store is triggered immediately: `[{ name: Joe }]`
// `callback` will be triggered each time when `.on` handler returns the new stateMost profit thing of stores.
Get smaller part of the store:
// `.map` accept state of parent store and return new memoized store. No more reselect ;)
const firstUser = users.map(list => list[0])
firstUser.watch(newState => console.log(`first user name: ${newState.name}`)) // "first user name: Joe"
addUser({name: Joseph}) // `firstUser` is not updated
getUsers() // after promise resolve `firstUser` is updated and call all watchers (subscribers)Compose stores:
import {createStore, createStoreObject} from 'effector'
const a = createStore(1)
const b = createStore('b')
const c = createStoreObject({a, b})
c.watch(console.log)
// => {a: 1, b: "b"}Domain is a namespace for your events, stores and effects. Domain can subscribe to event, effect, store or nested domain creation with onCreateEvent, onCreateStore, onCreateEffect, onCreateDomain(to handle nested domains) methods.
import {createDomain} from 'effector'
const mainPage = createDomain('main page')
mainPage.onCreateEvent(event => {
console.log('new event: ', event.getType())
})
mainPage.onCreateStore(store => {
console.log('new store: ', store.getState())
})
const mount = mainPage.event('mount')
// => new event: main page/mount
const pageStore = mainPage.store(0)
// => new store: 0
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