useevent.md

description	Dispatch events from the webcomponent without referencing the context(this)

useEvent

Syntax

const dispatchEvent = useEvent(myEvent, eventInit);

Where:

• dispatchEvent: callback, dispatches the event from the webcomponent and allows defining the detail by receiving a first parameter
• myEvent: string, name of the event to dispatch.
• eventInit: optional object, event configuration.

Examples

{% tabs %} {% tab title="Basic" %}

import { useEvent } from "atomico";

function component() {
  const dispatchEvent = useEvent("clickButton", {
    bubbles: true,
    composed: true,
  });
  return (
    <host>
      <button onclick={() => dispatchEvent()}>button</button>
    </host>
  );
}

{% endtab %}

{% tab title="Detail" %}

import { useEvent } from "atomico";

function component() {
  const dispatchEvent = useEvent("clickButton", {
    bubbles: true,
    composed: true,
  });
  return (
    <host>
      <button onclick={() => {
        const detail = "my-component"; // 👈
        dispatchEvent(detail);         // 👈
      }}>button</button>
    </host>
  )c

{% endtab %}

{% tab title="Typescript ⚡ " %}

import { Host, useEvent } from "atomico";

type DetailClickButton = {id: number};
//                             👇 declaration to associate event to JSX/TSX
function component():Host<{onclickButton: CustomEvent<DetailClickButton>}> {
//                             👇 type for detail
  const dispatchEvent = useEvent<DetailClickButton >("clickButton", {
    bubbles: true,
    composed: true,
  });
  return (
    <host>
      <button onclick={() => {
        //            👇 Detail
        dispatchEvent({id:100});
      }}>button</button>
    </host>
  );
}

{% endtab %} {% endtabs %}

Event customization

The second parameter of useEvent allows customizing the behavior of the even:

interface EventInit {
  // Allows the event to be dispatched upstream to the node's containers.
  bubbles?: boolean;
  // Allows the event to traverse the shadowDOM event capture.
  composed?: boolean;
  // Allows the event to be canceled.
  cancelable?: boolean;
  // Allows customizing the event builder, ideal for event instance-based communication.
  base?: Event | CustomEvent;
}

Recommended articles

{% content-ref url="../../guides/frequent-questions/how-to-declare-events-for-your-component-at-the-type-level-for-tsx.md" %} how-to-declare-events-for-your-component-at-the-type-level-for-tsx.md {% endcontent-ref %}