JSFiddle - React, Tailwind, and code Playground

HTML

<button>Carrega aqui para disparar um evento no elemento "p"</button>
<p>cobaia</p>

JavaScript

function acionar(target, type) {
    var doc = document;
    var event;
    if (doc.createEvent) {
        event = new Event(type);
        target.dispatchEvent(event);
    } else {
        event = doc.createEventObject();
        target.fireEvent('on' + type, event);
    }
};
var p = document.querySelector("p");
p.addEventListener("test.something", function (event) {
    alert(event.type + ' - ' +this.innerHTML);
});
document.querySelector("button").addEventListener('click', function (event) {
    acionar(p, "test.something");
});