gistfile1.txt

import React, { useState } from 'react';

export default function App() {
  
  const [ counter, setCounter] = useState(0);


  function Incrementar(){

    setCounter( counter + 1);
    return counter;

  }

  function Decrementar(){

    if(counter <= 0){
      alert("Não posso continuar");
    } else {
      setCounter( counter - 1);
      return counter;
    }

  }
  
  return (
    <>
      <h1> Contador: {counter} </h1>
      <button onClick={Incrementar}> Incrementar</button> <br/><br/>
      <button onClick={Decrementar}> Decrementar</button>
    </>
  );
}