JSFiddle - React, Tailwind, and code Playground

JavaScript

$(document).ready(function(){
   $("#assunto").autocomplete({
      source: function(request, response){
         $.ajax({
            dataType: 'json'
            url: "retornaCliente.php",
            data: {query: request.term},
            success: function(data){
               response(data);
            },
            error: function(jqXHR, textStatus, errorThrown){
               console.log(errorThrown);                        
            }
         });
      }
   });
});