Is there a way to append object in an array of object of type JSON field?

General
2

Every time you update a field it replaces the current value, that’s how updates works

If you want to achieve this functionality you have to take one or two extra steps

  1. Fetch all the data of row that you want to update.
  2. Take out wishlist property
  3. Push / Merge your body data to fetched wishlist data
  4. Update the entry with new merged data

You have to write a custom controller or extend the default update controller to achieve this functionality