JSFiddle - React, Tailwind, and code Playground

JavaScript

// OPEN YOUR CONSOLE =)


// Set up converter that runs when the
// dataType is "json test"
$.ajaxSetup({
  converters: {
    "json test": function( data ) {
        return "Went through converter";
    }
  }
});

// Setup ajax prefilter adds " test" to the dataType if the dataType is "json"
$.ajaxPrefilter(function( options ) {
    if ( options.dataType == "json" ) {
        console.log("Modifying the dataType on the fly for request number " + options.number );
        options.dataType += " test";
        console.log("dataType changed to 'json test' for request number " + options.number + "?", options.dataType == "json test");
    }
});

// The first request should hit the converter because
// it has the dataType of "json test",
// and it does. \o/
$.ajax({
    url : "/echo/json/",
    dataType: "json test",
    type: "POST",
    success: function( data ) {
        console.log( "Request 1", data );
    },
    number: 1
});

// The second request should hit the converter because it's
// dataType is "json" and is being dynamically changed to
// "json test" in the ajax prefilter, but it doesn't. /o\
//
// The data in the success callback should be "Went through converter",
// not an empty object.
$.ajax({
    url : "/echo/json/",
    dataType: "json",
    type: "POST",
    success: function( data ) {
        console.log( "Request 2", data );
    },
    number: 2
});