title: Vue.js can't get data in async methods
body: <p>I have a vue component sending a form to backend and getting JSON code. Then it set some data to show/hide messages on the template.</p>
  
  <p>But... I got an undefined error:</p>
  
  <blockquote>
    <p>"TypeError: Cannot set property 'sent' of undefined"</p>
  </blockquote>
  
  <p>Which means "this" not exists anymore. Why?</p>
  
  <pre><code>    export default {
      name: "contactsComponent",
  
      data: function(){
  
          return {
              sent: false,
              sentError: false,
              error: false,
          }
      },
  
      methods: {
          sendContact: async (e) =&gt; {
              e.preventDefault();
              const dataForm = serialize("contactForm");
              const {data} = await poRepository.sendContact(dataForm);
              console.log(data);
              this.sent = true;
              this.sentError = data.error;
           },
       }
    }
  </code></pre>