title: Vuex action returning jQuery promise doesn't work, .fail is not a function
body: <p>I have a vuex action like this</p>
  <pre><code>myAction() {
      const deferred = $.Deferred();
      setTimeout(() =&gt; deferred.resolve(), 3000);
      return deferred.promise();
  }
  </code></pre>
  <p>in my vue component</p>
  <pre><code>myMethod() {
      this.myAction().fail(() =&gt; ...do something...);
  }
  </code></pre>
  <p>throwing error:</p>
  <blockquote>
  <p>Uncaught TypeError: this.myAction(...).fail is not a function</p>
  </blockquote>
  <p>The code was working fine, but issue appeared once I updated my npm modules/vue-cli/webpack etc. Another point is if I change <code>.fail</code> to <code>.catch</code> then it works fine. But the question is why <code>.fail</code> is not working?</p>