text: import {
    useReducer,
    useRef,
    useEffect,
    useMemo,
    useLayoutEffect,
    useContext
  } from 'react'
  import invariant from 'invariant'
  import { useReduxContext as useDefaultReduxContext } from './useReduxContext'
  import Subscription from '../utils/Subscription'
  import { ReactReduxContext } from '../components/Context'
  
  // React currently throws a warning when using useLayoutEffect on the server.
  // To get around it, we can conditionally useEffect on the server (no-op) and
  // useLayoutEffect in the browser. We need useLayoutEffect to ensure the store
  // subscription callback always has the selector from the latest render commit
  // available, otherwise a store update may happen between render and the effect,
  // which may cause missed updates; we also must ensure the store subscription
  // is created synchronously, otherwise a store update may occur before the
  // subscription is created and an inconsistent state may be observed
  const useIsomorphicLayoutEffect =
    typeof window !== 'undefined' &&
    typeof window.document !== 'undefined' &&
    typeof window.document.createElement !== 'undefined'
      ? useLayoutEffect
      : useEffect
  
  const refEquality = (a, b) => a === b
  
  function useSelectorWithStoreAndSubscription(
    selector,
    equalityFn,
    store,
    contextSub
  ) {
    const [, forceRender] = useReducer(s => s + 1, 0)
  
    const subscription = useMemo(() => new Subscription(store, contextSub), [
      store,
      contextSub
    ])
  
    const latestSubscriptionCallbackError = useRef()
    const latestSelector = useRef()
    const latestSelectedState = useRef()
  
    let selectedState
  
    try {
      if (
        selector !== latestSelector.current ||
        latestSubscriptionCallbackError.current
      ) {
        selectedState = selector(store.getState())
      } else {
        selectedState = latestSelectedState.current
      }
    } catch (err) {
      let errorMessage = `An error occurred while selecting the store state: ${err.message}.`
  
      if (latestSubscriptionCallbackError.current) {
        errorMessage += `\nThe error may be correlated with this previous error:\n${latestSubscriptionCallbackError.current.stack}\n\nOriginal stack trace:`
      }
  
      throw new Error(errorMessage)
    }
  
    useIsomorphicLayoutEffect(() => {
      latestSelector.current = selector
      latestSelectedState.current = selectedState
      latestSubscriptionCallbackError.current = undefined
    })
  
    useIsomorphicLayoutEffect(() => {
      function checkForUpdates() {
        try {
          const newSelectedState = latestSelector.current(store.getState())
  
          if (equalityFn(newSelectedState, latestSelectedState.current)) {
            return
          }
  
          latestSelectedState.current = newSelectedState
        } catch (err) {
          // we ignore all errors here, since when the component
          // is re-rendered, the selectors are called again, and
          // will throw again, if neither props nor store state
          // changed
          latestSubscriptionCallbackError.current = err
        }
  
        forceRender({})
      }
  
      subscription.onStateChange = checkForUpdates
      subscription.trySubscribe()
  
      checkForUpdates()
  
      return () => subscription.tryUnsubscribe()
    }, [store, subscription])
  
    return selectedState
  }
  
  /**
   * Hook factory, which creates a `useSelector` hook bound to a given context.
   *
   * @param {Function} [context=ReactReduxContext] Context passed to your `<Provider>`.
   * @returns {Function} A `useSelector` hook bound to the specified context.
   */
  export function createSelectorHook(context = ReactReduxContext) {
    const useReduxContext =
      context === ReactReduxContext
        ? useDefaultReduxContext
        : () => useContext(context)
    return function useSelector(selector, equalityFn = refEquality) {
      invariant(selector, `You must pass a selector to useSelectors`)
  
      const { store, subscription: contextSub } = useReduxContext()
  
      return useSelectorWithStoreAndSubscription(
        selector,
        equalityFn,
        store,
        contextSub
      )
    }
  }
  
  /**
   * A hook to access the redux store's state. This hook takes a selector function
   * as an argument. The selector is called with the store state.
   *
   * This hook takes an optional equality comparison function as the second parameter
   * that allows you to customize the way the selected state is compared to determine
   * whether the component needs to be re-rendered.
   *
   * @param {Function} selector the selector function
   * @param {Function=} equalityFn the function that will be used to determine equality
   *
   * @returns {any} the selected state
   *
   * @example
   *
   * import React from 'react'
   * import { useSelector } from 'react-redux'
   *
   * export const CounterComponent = () => {
   *   const counter = useSelector(state => state.counter)
   *   return <div>{counter}</div>
   * }
   */
  export const useSelector = createSelectorHook()
  