Using Fetch with Wordpress Plugins Ajax

fetch_plugin.js

fetch(ajax_url, {
      method: 'POST',
      credentials: 'same-origin',
      headers: new Headers({'Content-Type': 'application/x-www-form-urlencoded'}),
      body: 'action=zget_profile_user'
    })
    .then((resp) => resp.json())
    .then(function(data) {
      if(data.status == "success"){
        _this.setState({loaded:true,user:data.user});
      }
    })
    .catch(function(error) {
      console.log(JSON.stringify(error));
    });

This is killer! Thank you. I was able to modify this to download a PDF file from the server.

Is there any demo or code for GET REQUEST in ajax?