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/*export {  unstable_createMutableSource as createMutableSource,  unstable_useMutableSource as useMutableSource,} from 'react'*/
// useMutableSource emulation almost equivalent to useSubscription
import { useEffect, useRef, useState } from 'react'
const TARGET = '_uMS_T'const GET_VERSION = '_uMS_V'
type MutableSource<T, V> = {  [TARGET]: T  [GET_VERSION]: (target: T) => V}
export const createMutableSource = <T, V>(  target: T,  getVersion: (target: T) => V): MutableSource<T, V> => ({  [TARGET]: target,  [GET_VERSION]: getVersion,})
export const useMutableSource = <T, V, S>(  source: MutableSource<T, V>,  getSnapshot: (target: T) => S,  subscribe: (target: T, callback: () => void) => () => void) => {  const lastVersion = useRef<V>()  const currentVersion = source[GET_VERSION](source[TARGET])  const [state, setState] = useState(    () =>      [        /* [0] */ source,        /* [1] */ getSnapshot,        /* [2] */ subscribe,        /* [3] */ currentVersion,        /* [4] */ getSnapshot(source[TARGET]),      ] as const  )  let currentSnapshot = state[4]  if (    state[0] !== source ||    state[1] !== getSnapshot ||    state[2] !== subscribe  ) {    currentSnapshot = getSnapshot(source[TARGET])    setState([      /* [0] */ source,      /* [1] */ getSnapshot,      /* [2] */ subscribe,      /* [3] */ currentVersion,      /* [4] */ currentSnapshot,    ])  } else if (    currentVersion !== state[3] &&    currentVersion !== lastVersion.current  ) {    currentSnapshot = getSnapshot(source[TARGET])    if (!Object.is(currentSnapshot, state[4])) {      setState([        /* [0] */ source,        /* [1] */ getSnapshot,        /* [2] */ subscribe,        /* [3] */ currentVersion,        /* [4] */ currentSnapshot,      ])    }  }  useEffect(() => {    let didUnsubscribe = false    const checkForUpdates = () => {      if (didUnsubscribe) {        return      }      try {        const nextSnapshot = getSnapshot(source[TARGET])        const nextVersion = source[GET_VERSION](source[TARGET])        lastVersion.current = nextVersion        setState((prev) => {          if (            prev[0] !== source ||            prev[1] !== getSnapshot ||            prev[2] !== subscribe          ) {            return prev          }          if (Object.is(prev[4], nextSnapshot)) {            return prev          }          return [            /* [0] */ prev[0],            /* [1] */ prev[1],            /* [2] */ prev[2],            /* [3] */ nextVersion,            /* [4] */ nextSnapshot,          ]        })      } catch (e) {        // schedule update        setState((prev) => [...prev])      }    }    const unsubscribe = subscribe(source[TARGET], checkForUpdates)    checkForUpdates()    return () => {      didUnsubscribe = true      unsubscribe()    }  }, [source, getSnapshot, subscribe])  return currentSnapshot}