useContext-example.js

import React, { useContext } from 'react';
import logo from './logo.svg';
import './App.css';

const AppContext = React.createContext({ theme: null, nome: null });

function Post() {
  const theme = useContext(AppContext);
  return (
    <div className="{theme}">
      {console.log(theme)}
      <h1>My posts</h1>
    </div>
  );
}

const Profile = () => {
  const context = useContext(AppContext);
  console.log(context.name);
  return (
    <div className="dados">
      <p>Nome: {context.name} - {context.lastname}</p>
    </div>
  );
};

function App() {
  return (
    <div className="App">
      <AppContext.Provider value="dark">
        <Post />
      </AppContext.Provider>
      <AppContext.Provider value={ { name: "jp", lastname: "ok" }}>
        <Profile />
      </AppContext.Provider>
      <header className="App-header">
        <img src={logo} className="App-logo" alt="logo" />
        <p>
          Edit <code>src/App.js</code> and save to reload.
        </p>
        <a
          className="App-link"
          href="https://reactjs.org"
          target="_blank"
          rel="noopener noreferrer"
        >
          Learn React
        </a>
      </header>
    </div>
  );
}

export default App;