redux like concept with react 16 context and react 16.7 beta hooks (https://codesandbox.io/s/jvklvmp8l9)

App.jsx

import React from "react";
import Provider from "./Provider";
import Counter from "./Counter";

const App = ({ reducer, initialState }) => {
  return (
    <Provider reducer={reducer} initialState={initialState}>
      <Counter />
    </Provider>
  );
};

export default App;

context.js

import { createContext } from "react";

export const StoreContext = createContext({});

Counter.jsx

import React, { useContext } from "react";
import { StoreContext } from "./context";

const Counter = () => {
  const [state, dispatch] = useContext(StoreContext);

  return (
    <>
      Count: {state.count}
      <button onClick={() => dispatch({ type: "reset" })}>Reset</button>
      <button onClick={() => dispatch({ type: "increment" })}>+</button>
      <button onClick={() => dispatch({ type: "decrement" })}>-</button>
    </>
  );
};

export default Counter;

index.js

import React from "react";
import { render } from "react-dom";
import App from "./App";

const initialState = { count: 0 };

function reducer(state, action) {
  switch (action.type) {
    case "reset":
      return initialState;
    case "increment":
      return { count: state.count + 1 };
    case "decrement":
      return { count: state.count - 1 };
    default:
      return state;
  }
}

render(
  <App reducer={reducer} initialState={initialState} />,
  document.getElementById("root")
);

Provider.jsx

import React, { useReducer } from "react";
import { StoreContext } from "./context";

const Provider = ({ reducer, initialState, children }) => {
  const store = useReducer(reducer, initialState);

  return (
    <StoreContext.Provider value={store}>
      {children}
    </StoreContext.Provider>
  );
};

export default Provider;

Components and logic from https://reactjs.org/docs/hooks-reference.html#usereducer