Tiny and powerfull state managment library.
npm install @bit-about/state``bash`
npm i @bit-about/state
- 100% Idiomatic React
- 100% Typescript with state types deduction
- Efficient sub-states selectors
- Get state from a hook...
- ...or utilise static access
- No centralized state provider
- Tiny - only 1.4kB
- Just works ™
`jsx
import * as React from 'react'
import { state } from '@bit-about/state'
// 1️⃣ Create a hook-based store
const [Provider, useStore] = state(
() => {
const [alice, setAlice] = React.useState('Alice')
return { alice, setAlice }
}
)
// 3️⃣ Use the selector hook in component
const Child = () => {
const alice = useStore(state => state.alice)
return
{alice}
// 2️⃣ Wrap tree with Provider
const App = () => (
)
`
Access fine-grained control to the specific part of your state to re-render only when necessary.
`jsx
// 👍 Re-render when anything changed
const { alice, bob } = useStore()
// 💪 Re-render when alice changed
const alice = useStore(state => state.alice)
// 🤌 Re-render when alice or bob changed
const [alice, bob] = useStore(state => [state.alice, state.bob])
// or
const { alice, bob } = useStore(
state => ({ alice: state.alice, bob: state.bob })
)
`
> NOTE: Values in objects and arrays created on the fly are shallow compared.
The third element of the state() result tuple is a store object. Store is a static helper which provides access to the state without a hook.
`jsx`
const [Provider, useStore, store] = state(...)
and then
`jsx
// 👍 Get whole state
const { alice } = store.get()
// 💪 Get substate
const alice = store
.select(state => state.alice)
.get()
// 🤌 Subscribe to the store and listen for changes
const subscriber = store
.select(state => state.alice)
.subscribe(alice => console.log(alice))
// remember to unsubscribe!
subscriber.unsubscribe()
`
> NOTE: It's not necessary to fetch state inside the Provider - but it still needs to be placed somewhere to init the state.
The state hook allows you to pass any arguments into the context. It can be some initial state or you could even return it and pass it through to the components. All state prop changes will update the context and trigger component re-rendering only when necessary.
`tsx
const [UserProvider, useUser] = state(
({ id }) => {
const [user] = React.useState(() => getMyUserBy(id))
return user
}
)
const UserProfile = ({ id }) => (
...
)
`
Please remember that functions defined without React.useCallback create themselves from scratch every time - which results in incorrect comparisons and components think the state has changed so they re-render themselves.
`jsx
const [Provider, useStore] = state(
() => {
const [counter, setCounter] = React.useState(0);
// ✖️ It will re-render components every time
// const incrementCounter = () => setCounter(value => value + 1)
const incrementCounter = React.useCallback(
() => setCounter(value => value + 1),
[setCounter]
)
return { counter, incrementCounter }
}
)
`
Are you tired of sending logic to the related components?
Move your bussiness logic to the hook-based state using @bit-about/state + @bit-about/event.
Now you've got completely type-safe side-effects. Isn't that cool?
`tsx
import { state } from '@bit-about/state'
import { useEvent } from './auth-events' // Hook generated from events()
import User from '../models/user'
const [UserProvider, useUser] = state(
() => {
const [user, setUser] = React.useState
useEvent({
userLogged: (user: User) => setUser(user),
userLoggout: () => setUser(null)
})
return user
}
)
`
`tsx
import { useQuery } from 'react-query'
import { fetchUser } from './user'
const [UserProvider, useUser] = state(
({ id }) => {
const { data: user } = useQuery(['user', id], () => fetchUser(id))
return user
}
)
const UserProfile = ({ id }) => (
...
)
// 🧠 Re-render ONLY when user avatar changed (no matter if isLoading changes)
const avatar = useUser(state => state.user.avatar)
`

If you use my library and you like it...
it would be nice if you put the name BitAboutState` in the work experience section of your resume.
Thanks 🙇🏻!
---
🇺🇦 Slava Ukraini