title: TypeError: cyclic object value in React
body: <p>This is my code:</p>
  
  <pre><code>sendMail(e) {
      e.preventDefault();
      // fetch('/https://uczsieapp-mailer.herokuapp.com/', {
      var name = document.getElementById('name');
      var contactReason = document.getElementById('contactReason');
      var email = document.getElementById('email');
      var additionalInfo = document.getElementById('additionalInfo');
      var body = JSON.stringify({
              name: name,
              contactReason: contactReason,
              email: email,
              additionalInfo: additionalInfo,
          }
      );
      console.log(body);
      fetch('http://localhost:4000/', {
          method: 'POST',
          body: JSON.stringify({
                  name: name,
                  contactReason: contactReason,
                  email: email,
                  additionalInfo: additionalInfo,
              }
          )
      });
  }
  </code></pre>
  
  <p>The code references this HTML:</p>
  
  <pre><code>&lt;form&gt;
      &lt;input className="form_input input_margin" type="text" id='name' name="name"
             placeholder="Imię"/&gt;
      &lt;input className="form_input_2" type="text" name="email" id='email'
             placeholder="Adres e-mail"/&gt;
      &lt;textarea name='additionalInfo' id='additionalInfo' className="form_textarea"
                type="text" placeholder="Dodatkowe informacje"/&gt;
      &lt;button onClick={this.sendMail} className="btn button_send"&gt;Wyślij&lt;/button&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>So what I understand it's referencing something, that's being changed, but how does anyone know where exactly this error is and why?</p>
  
  <p>I get this error on the <code>JSON.stringify()</code> method. Creating an object without <code>stringify()</code> works.</p>