Install

npm i @bit-about/event

Migrations

Events dispatch approach has been changed. There are no longer functions executed using their names in string.

✖️ old one:

const dispatch = useEvent()
dispatch('onBobPress', 'hello') 

✅ new one:

const { onBobPress } = useEvent()
onBobPress('hello')

Features

• 100% Idiomatic React
• 100% Typescript with event types deduction
• Listen or dispatch events from a hook...
• ...or utilise static access
• No centralized event provider
• Tiny - only 0.6kB
• Just works ™

➡️ Check demo

Usage

1️⃣ Define your events by defining their payload middlewares

import { events } from '@bit-about/event'

const [EventProvider, useEvents] = events({
  buttonClicked: (payload: string) => payload,
  userLogged: () => {},
  modalClosed: () => {},
})

2️⃣ Wrap your components in EventProvider

const App = () => (
  <EventProvider>
    ...
  </EventProvider>
)

🗣️ Dispatch your events in one place...

const Button = () => {
  const { buttonClicked } = useEvents()
  
  return (
    <button onClick={() => buttonClicked('Hello')}>
      Call event
    </button>
  )
}

👂 ...and listen for them in another

const Component = () => {
  const [message, setMessage] = React.useState('')

  useEvents({
    buttonClicked: (payload: string) => setMessage(payload)
  })
  
  return <p>{message}</p> // "Hello"
}

Static access

The third result element of events() is object providing access in static manner (without hook).

const [AppEventProvider, useAppEvents, { subscribe, dispatcher }] = events(...)

and then

// 🗣️ Dispatch event
dispatcher.buttonClicked('Hello Allice!')

// 👂 Subscribe and listen on new events
const subscriber = subscribe({
  buttonClicked: (payload: string) => console.log(payload)
})
  
// remember to unsubscribe!
subscriber.unsubscribe()

👉 Re-render

Neither listeners nor events dispatch your components render. A component will only be rerendered if it's state is explicitly changed (in e.g. React.useState).

const Component = () => {
  const [message, setMessage] = React.useState('')

  useEvents({
    aliceClicked: () => console.log('I DO NOT rerender this component!'),
    bobClicked: () => setMessage('I DO rerender this component!')
  })
  
  return <p>{message}</p>
}

Event Middlewares

Events in events() are payload middlewares. They can transform payload into another.

const [EventProvider, useEvents] = events({
  buttonClicked: (payload) => `Hello ${message}!`, // Transforms string payload to another
  avatarClicked: () => `Bob!`,                     // Provides default payload
})

const { buttonClicked, avatarClicked } = useEvents({
  buttonClicked: (payload) => console.log(payload), // prints "Hello Alice!",
  avatarClicked: (payload) => console.log(payload), // prints "Bob!"
})

buttonClicked('Alice')
avatarClicked()

NOTE: The library is full type-safe, so Typescript will inform you when you use wrong payload anywhere.

BitAboutEvent 💛 BitAboutState

Are you tired of sending logic to a related components? Move your bussiness logic to hook-based state using @bit-about/state + @bit-about/event.

Now you've got completely type-safe side-effects. Isn't that cool?

import { state } from '@bit-about/state'
import { useEvents } from './auth-events' // Hook generated from events()
import User from '../models/user'

const [UserProvider, useUser] = state(
  () => {
    const [user, setUser] = React.useState<User | null>(null)
    
    useEvents({
      userLogged: (user: User) => setUser(user),
      userLoggout: () => setUser(null)
    })
    
    return user
  }
)

Partners

Credits

• Constate - approach main inspiration
• use-context-selector & FluentUI - fancy rerender avoiding tricks and code main inspiration

License

MIT © Maciej Olejnik 🇵🇱

Support me

If you use my library and you like it... it would be nice if you put the name BitAboutEvent in the work experience section of your resume. Thanks 🙇🏻!