JSFiddle - React, Tailwind, and code Playground

HTML

<!--
 Is this a bug or feature?

 jQuery does not add a key component for undefined values

(Tested with 1.4.4, 1.5.2)

-->

JavaScript

$(function() {
    var MyObj = {};
    var params= {"MyKey": "MyValue", "OtherKey": MyObj.UndefinedKey, "ThirdKey": ""};
    var foo = $.param(params, false);
                
    $.ajax({
        type: 'GET',
        url: 'http://example.com/SomePage',
        data: params,
        complete: function(xhr, textStatus) {
            $("body").html("Params: " + foo + "<br/>URL: " + this.url);    
        }
    });
});