/
idyl.js
63 lines (50 loc) · 1.26 KB
/
idyl.js
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import { useState, useRef, useEffect, useLayoutEffect, useMemo } from 'react'
const useLayout = typeof window === 'undefined' ? useEffect : useLayoutEffect
function create(initial) {
const state = initial
const listeners = new Set()
function subscribe(listener) {
listeners.add(listener)
return () => {
listeners.delete(listener)
}
}
function setState(key, value) {
if (!Object.is(state[key], value)) {
state[key] = value
}
listeners.forEach((listener) => listener(state, key))
}
function useStore() {
const rerender = useState()[1]
const tracked = useRef({})
const stateRef = useRef(state)
const proxy = useMemo(() => {
stateRef.current = state
return new Proxy(
{},
{
get(_, property) {
tracked.current[property] = true
return stateRef.current[property]
},
set(_, property, value) {
setState(property, value)
return true
},
}
)
}, [])
useLayout(() => {
const unsub = subscribe((_, key) => {
if (tracked.current[key]) {
rerender({})
}
})
return unsub
}, [])
return proxy
}
return useStore
}
export default create