re-implementation of redux and react-redux by 52 LOC https://www.webpackbin.com/bins/-KhSxnW73-R4iCMwdfnW

ledux.js

import React from "react";

let store;
export default function createStore(
  reducer,
  initialState = {},
  ...middlewares
) {
  const subscribers = [];
  let newState = initialState;
  store = {
    dispatch: action => {
      newState = reducer(initialState, action);
      subscribers.forEach(f => f(newState, store.dispatch));
    },
    getState: () => newState,
    subscribe: cb => {
      subscribers.push(cb);
      return () => subscribers.splice(subscribers.indexOf(cb), 1);
    }
  };
  return store;
}

const getStore = () => store;

export const connect = (mapStateToProps = e => null, mapDispatchToProps) =>
  Component =>
    class ConnectedComponent extends React.Component {
      constructor(props) {
        super(props);
        this.store = getStore();
        this.state = mapStateToProps(this.store.getState())
        this.unsubscribe = this.store.subscribe(()=>{
          this.setState(mapStateToProps(this.store.getState()))
        });
      }
      componentWillUnmount(){
        this.unsubscribe()
      }
      render() {
        return (
          <Component
            {...this.props}
            {...this.state}
            {...mapDispatchToProps
              ? mapDispatchToProps(this.store.dispatch)
              : { dispatch: this.store.dispatch }}
          />
        );
      }
    };