是否可以通过 useCallback 避免自定义 React Hook 上的“eslint(react-hooks/exhaustive-deps)”错误？

Question

Take the following custom React Hook to interact with IntersectionObserver :

import { useCallback, useRef, useState } from 'react';

type IntersectionObserverResult = [(node: Element | null) => void, IntersectionObserverEntry?];

function useIntersectionObserver(options: IntersectionObserverInit): IntersectionObserverResult {
    const intersectionObserver = useRef<IntersectionObserver>();

    const [entry, setEntry] = useState<IntersectionObserverEntry>();

    const ref = useCallback(
        (node) => {
            if (intersectionObserver.current) {
                console.log('[useInterSectionObserver] disconnect(🔴)');
                intersectionObserver.current.disconnect();
            }

            if (node) {
                intersectionObserver.current = new IntersectionObserver((entries) => {
                    console.log('[useInterSectionObserver] callback(🤙)');
                    console.log(entries[0]);

                    setEntry(entries[0]);
                }, options);

                console.log('[useInterSectionObserver] observe(🟢)');
                intersectionObserver.current.observe(node);
            }
        },
        [options.root, options.rootMargin, options.threshold]
    );

    return [ref, entry];
}

export { useIntersectionObserver };

ESLint is complaining about:

React Hook useCallback has a missing dependency: 'options'. Either include it or remove the dependency array.

If I replace the dependencies array with [options] , ESLint no longer complains but there's now a much bigger problem, a rendering infinite loop .

What would be the right way to implement this custom React Hook without having the eslint(react-hooks/exhaustive-deps) error showing up?

Answer 1

The fix to this is to destructure the properties you need from options and set them in the dependancy array. That way you don't need options and the hook only gets called when those three values change.

import { useCallback, useRef, useState } from 'react';

type IntersectionObserverResult = [(node: Element | null) => void, IntersectionObserverEntry?];

function useIntersectionObserver(options: IntersectionObserverInit): IntersectionObserverResult {
    const intersectionObserver = useRef<IntersectionObserver>();
    const [entry, setEntry] = useState<IntersectionObserverEntry>();
    const { root, rootMargin, threshold } = options;

    const ref = useCallback(
        (node) => {
            if (intersectionObserver.current) {
                console.log('[useInterSectionObserver] disconnect(🔴)');
                intersectionObserver.current.disconnect();
            }

            if (node) {
                intersectionObserver.current = new IntersectionObserver((entries) => {
                    console.log('[useInterSectionObserver] callback(🤙)');
                    console.log(entries[0]);

                    setEntry(entries[0]);
                }, options);

                console.log('[useInterSectionObserver] observe(🟢)');
                intersectionObserver.current.observe(node);
            }
        },
        [root, rootMargin, threshold]
    );

    return [ref, entry];
}

export { useIntersectionObserver };

Answer 2

You should always provide all the necessary values in the dep array to prevent it from using the previous cached function with stale values. One option to fix your situation is to memo the options object so only a new one is being passed when it's values change instead of on every re-render:

// in parent
// this passes a new obj on every re-render
const [ref, entry] = useIntersectionObserver({ root, rootMargin, threshold }); 

// this will only pass a new obj if the deps change
const options = useMemo(() => ({ root, rootMargin, threshold }), [root, rootMargin, threshold]);
const [ref, entry] = useIntersectionObserver(options);