JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    <input name="field1" type="text" class="field" />
    <input name="field2" type="text" class="field" />
    <input name="field3" type="text" class="field" />
    <br/><br/>
    <input name="field4" type="text" class="ajax-field" />
    <input name="field5" type="text" class="ajax-field" />
</form>

JavaScript

var timer;

$(document).ready(function() {
    var fields = $('.field');
    var ajaxFields = $('.ajax-field');
    
    createEvents(fields, ajaxFields);
});

function createEvents(fields,ajaxFields) {
    $(fields).each(function(inx, field) {
        $(field).keyup(function(ev) {
            if (timer != null) clearTimeout(timer);
            
            timer = setTimeout(function() {
                console.log('Fields: ', fields, '\nAjax Fields: ', ajaxFields, '\nTHE field: ', field);
            }, 1000);
        });
    });
}