controlledComponent.js

import React, { useState } from "react";

export default function App() {
  const [inputValue, setInputValue] = useState("");
  const handleSubmitButton = () => {
    alert(inputValue);
  };
  return (
    <div className="App">
      <input value={inputValue} onChange={e => setInputValue(e.target.value)} />
      <input type="submit" value="submit" onClick={handleSubmitButton} />
    </div>
  );
}