README

use-simple-store 🏬

Simple global state management using react hook.

Install

npm i use-simple-store

Example

import createStore from 'use-simple-store'

const { useStore, update } = createStore({ count: 0 })

const increment = () => update(state => {
    state.count = state.count + 1
})

const decrement = () => update(state => {
    state.count = state.count - 1
})

function App() {
    const { count } = useStore()

    return (
        <div>
            <span>{count}</span>
            <button onClick={decrement}> - </button>
            <button onClick={increment}> + </button>
        </div>))
}

API

createStore(initialState)

Create a store.

store.update([mutate])

Update state by mutate function. (using immer)

const todos = createStore({})

const addTodo = (id, text) => todos.update(state => {
    state[id] = { id, text, done: false }
})

const deleteTodo = id => todos.update(state => {
    delete state[id]
})

Asynchronous update.

The update() does not support promise. If you need an asynchronous update, see the example below: 👇

async function fetchTodos() {
    update(state => {
        state.fetching = true
    })

    const todos = await fetchTodosAsync()

    update(state => {
        state.fetching = false
        state.todos = todos
    })
}

store.subscribe(listener)

Subscribe to state changes.

const { subscribe, update } = createStore({count: 0})

subscribe(state => {
    console.log(`count: ${state.count}`)
})

update(state => { state.count++ }) // => count: 1
update(state => { state.count++ }) // => count: 2

Unsubscribe

The subscribe() returns a function to unsubscribe.

const unsubscribe = subscribe(listener)

/* ... */

unsubscribe()

store.getState()

Returns current state.

store.useStore([selector[, dependencies]])

A react hook to subscribe to store state changes.

selector

Select only the necessary state of the store. When the state of the store is large, its performance is better.

function Todo({ id }) {
    const todo = useStore(state => state[id])

    const handleClick = () => {
        update(state => {
            state[id].done = !todo.done
        })
    }

    return <li onClick={handleClick}>{todo.text}</li>)
}

dependencies

Replace the selector with dependencies.

const s = useStore(state => state[condition ? 'v1':'v2'], [condition])

License

MIT

Usage no npm install needed!