title: Issues with passing all values entered on a form, via formData, with fetch API
body: <p>Why formData goes empty to my express+mongodb server? I've some problems with querySelector and addEventListener, but for now thats ok. However, I don't find a way for sending all values of my form to the server. Please, someone help me?</p>
  
  <pre><code>document.querySelector('#enviar- 
  cadastro').addEventListener('click', Cadastrar);
  
  
  Cadastrar('http://localhost:5000/usuario/novo')
   .then(response =&gt; console.log(response.json()))
   .then(data =&gt; console.log(data))
   .catch(error =&gt; console.log(error));
  
   function Cadastrar(url) {
     const formDados = new FormData(document.querySelector('#signup'))
  
     return fetch(url, {
      method: 'POST',
      body: JSON.stringify(formDados),
          headers: {
              "Content-Type": "application/json"
          }
     })
  
   };
  </code></pre>