$.fn.triggerHandler(name, data?)

Invoke the handlers bound to the first element in the collection without dispatching a real DOM event. No event bubbles, no native default action runs, and the return value of the last matching handler is returned to the caller, which makes .triggerHandler() ideal for treating event handlers as ordinary functions whose result you want to read.

Each matching handler receives a synthetic event-like object with target, currentTarget, and arg properties — the supplied data is exposed as arg rather than detail.

Signatures

triggerHandler(name: string, data?: unknown): unknown;

Parameters

• name (string) — The event name whose bound handlers should be invoked.
• data (unknown, optional) — A value passed to handlers via the synthetic event’s arg property.

Returns

The return value of the last matching handler, or undefined if no handler is bound to that event on the first element.

Examples

import $ from "dabbyjs";
import "dabbyjs/events/on/on";
import "dabbyjs/events/triggerhandler/triggerhandler";

// Run a validation handler and read its return value
$("form").on("validate", function () {
    return (this as HTMLFormElement).checkValidity();
});

const isValid = $("form").triggerHandler("validate") as boolean;
if (!isValid) {
    console.log("form has errors");
}

import $ from "dabbyjs";
import "dabbyjs/events/on/on";
import "dabbyjs/events/triggerhandler/triggerhandler";

// Compute a value from the first matching element without changing the DOM
$(".price").on("calculateTotal", function () {
    const price = parseFloat(this.textContent ?? "0");
    const quantity = Number((this as HTMLElement).dataset.quantity ?? "1");
    return price * quantity;
});

const total = $(".price").triggerHandler("calculateTotal") as number;
$(".total").text(`£${total.toFixed(2)}`);

import $ from "dabbyjs";
import "dabbyjs/events/on/on";
import "dabbyjs/events/triggerhandler/triggerhandler";

// Run a click handler without following the link
$("a[href='#save']").on("click", function (event) {
    event.preventDefault();
    saveDocument();
    return "saved";
});

const result = $("a[href='#save']").triggerHandler("click");
console.log(result); // "saved"

declare function saveDocument(): void;

import $ from "dabbyjs";
import "dabbyjs/events/on/on";
import "dabbyjs/events/triggerhandler/triggerhandler";

// When several handlers are bound, only the last return value comes back
$("button").on("process", () => "step1");
$("button").on("process", () => "step2");

const last = $("button").triggerHandler("process");
console.log(last); // "step2"

See also

• $.fn.trigger() — dispatch a real bubbling event
• $.fn.on() — bind handlers
• $.fn.off() — remove bound handlers

Differences from jQuery

Does not support the jQuery.Event wrapper. Only handlers attached through Dabby’s .on() are invoked — native listeners attached directly with addEventListener are not. Only the first element in the collection is processed, matching jQuery’s behaviour.