HomeWork/react2/node_modules/react-redux/es/components/Provider.js

import React, { useMemo } from 'react';
import PropTypes from 'prop-types';
import { ReactReduxContext } from './Context';
import { createSubscription } from '../utils/Subscription';
import { useIsomorphicLayoutEffect } from '../utils/useIsomorphicLayoutEffect';

function Provider(_ref) {
  var store = _ref.store,
      context = _ref.context,
      children = _ref.children;
  var contextValue = useMemo(function () {
    var subscription = createSubscription(store);
    subscription.onStateChange = subscription.notifyNestedSubs;
    return {
      store: store,
      subscription: subscription
    };
  }, [store]);
  var previousState = useMemo(function () {
    return store.getState();
  }, [store]);
  useIsomorphicLayoutEffect(function () {
    var subscription = contextValue.subscription;
    subscription.trySubscribe();

    if (previousState !== store.getState()) {
      subscription.notifyNestedSubs();
    }

    return function () {
      subscription.tryUnsubscribe();
      subscription.onStateChange = null;
    };
  }, [contextValue, previousState]);
  var Context = context || ReactReduxContext;
  return /*#__PURE__*/React.createElement(Context.Provider, {
    value: contextValue
  }, children);
}

if (process.env.NODE_ENV !== 'production') {
  Provider.propTypes = {
    store: PropTypes.shape({
      subscribe: PropTypes.func.isRequired,
      dispatch: PropTypes.func.isRequired,
      getState: PropTypes.func.isRequired
    }),
    context: PropTypes.object,
    children: PropTypes.any
  };
}

export default Provider;