useEvent

A stable callback that always runs its handler untracked. The ShadowJS form of React's useEffectEvent: components run once and props are getters, so the handler already sees the latest values. What it adds is the untracked call: an effect that calls the event does not subscribe to the signals the handler reads.

Import#

import { useEvent } from "@shadow-js/core";

Signature#

function useEvent<A extends unknown[], R>(handler: (...args: A) => R): (...args: A) => R

Parameters#

Returns#

A new function with the same signature that calls handler untracked. Create it once, in the component body, and keep the reference.

Examples#

import { useEffect, useEvent, useSignal } from "@shadow-js/core";

function Ticker() {
  const [count] = useSignal(0);
  const onTick = useEvent(() => console.log(count())); // count() is not tracked by the effect
  useEffect(() => {
    const id = setInterval(() => onTick(), 1000);
    return () => clearInterval(id);
  });
  return null;
}