Антон Тарасов

fetch(ajaxSettings.ajaxurl, {
      method: 'POST',
      credentials: 'same-origin',
      headers: {
       'Content-Type': 'application/x-www-form-urlencoded',
       'Cache-Control': 'no-cache',
      },
      body: params
    }).then(response => {
       return response.json();
    })
    .then(response => {
       // read data here
       console.log(response);
     }).catch(err => { 
       console.log(err);
     });