如何使用React从表单输入和api调用中声明全局变量？

import React from 'react';

const AppContext = React.createContext();

export default AppContext;

import React from 'react';
import AppContext from './AppContext';

function App() {
  const globalVariable = 'Hello, World!';

  return (
    <AppContext.Provider value={globalVariable}>
      {/* 其他组件 */}
    </AppContext.Provider>
  );
}

export default App;

import React from 'react';
import AppContext from './AppContext';

function ChildComponent() {
  return (
    <AppContext.Consumer>
      {globalVariable => (
        <div>{globalVariable}</div>
      )}
    </AppContext.Consumer>
  );
}

export default ChildComponent;