use-constant-handler v0.1.9

use-constant-handler

React hooks for make constant pointer to function/handler

Usage

import { useConstHandler } from "use-constant-handler";

const Component = ({ onEvent, onInit }) => {
    // pointer to onInit callback can changed, but pointor to initHandler don't change
    const onInitHandler = useConstFunc(() => onInit());
    useEffect(() => {
        onInitHandler();
    }, [onInitHandler]); //it will call only once becouse initHandler don`t change


    // We do not need redraw input when onEvent callback change.
    // New onEvent callback need only when SubComponent call onEvent.
    // Pointer to onChange callback can changed,
    // but pointor to onChangeHandler don't change
    const onEventHandler = useConstHandler((e) => onEvent(e))
    return <SubComponent onEvent={onEventHandler}/>;
}

Description

Source code of useConstFunc:

const useConstFunc = (f) => {
	const { current } = useRef((...args) => current[FUNC_KEY]?.(...args));
	current[FUNC_KEY] = f;
	return current;
};

Source code of useConstHandler:

const useConstHandler = (f) => {
    const { current } = useRef((...args) => (current[FUNC_KEY] ?? f)(...args));

    useLayoutEffect(() => {
        current[FUNC_KEY] = f;
    });

    return current;
};