title: how to add an array of objects in a fetch request
body: <p>i'm trying to add a post request containing an array of objects and i'm stuck. Could you help me and guide me where my problem is?</p>
  <p><a href="https://i.stack.imgur.com/EoO6q.png" rel="nofollow noreferrer">this is my code</a></p>
  <p><a href="https://i.stack.imgur.com/bS72M.png" rel="nofollow noreferrer">this is what i want to save</a></p>