title: Fetch() api in react native failed - "Unhandled promise rejection"
body: <p>Im trying to use the Fetch api in react native but im having some issues. Whenever I try to make a POST, i get a "Unhandled promise rejection" error saying the body not allowed for GET or HEAD reequests.</p>
  
  <p>The GET method works perfectly fine, it's just with POST.</p>
  
  <p>Any ideas?</p>
  
  <pre><code>submit_task() {
      this.setModalVisible(!this.state.modalVisible);
      const task = {
          text: this.state.content,
          date: this.state.date
      }
      console.log(task);
  
      const API_URL = 'http://localhost:5000/tasks';
      fetch(API_URL, {
          methood: 'POST',
          body: JSON.stringify(task),
          headers: {
              'Content-Type': 'application-json',
          }
      })
  }
  </code></pre>