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🤙 use-callback-ref 📞


The same `useRef` but it will callback: 📞 Hello! Your ref was changed!
Travis bundle size

Keep in mind that useRef doesn't notify you when its content changes. Mutating the .current property doesn't cause a re-render. If you want to run some code when React attaches or detaches a ref to a DOM node, you may want to use a callback ref instead .... useCallbackRef instead.

– Hooks API Reference

Read more about use-callback pattern and use cases:

This library exposes helpers to handle any case related to ref lifecycle

  • useCallbackRef - react on a ref change (replacement for useRef)
    • createCallbackRef - - low level version of useCallbackRef
  • useMergeRefs - merge multiple refs together creating a stable return ref
    • mergeRefs - low level version of useMergeRefs
  • useTransformRef - transform one ref to another (replacement for useImperativeHandle)
    • transformRef - low level version of useTransformRef
  • useRefToCallback - convert RefObject to an old callback-style ref
    • refToCallback - low level version of useRefToCallback
  • assignRef - assign value to the ref, regardless it is RefCallback or RefObject

All functions are tree shakable, but even together it's less then 300b.

API

💡 Some commands are hooks based, and returns the same refs/functions every render. But some are not, to be used in classes or non-react code.

useRef API

🤔 Use case: every time you have to react to ref change

API is 99% compatible with React createRef and useRef, and just adds another argument - callback, which would be called on ref update.

createCallbackRef - to replace React.createRef

  • createCallbackRef(callback) - would call provided callback when ref is changed.

useCallbackRef - to replace React.useRef

  • useCallbackRef(initialValue, callback) - would call provided callback when ref is changed.

callback in both cases is callback(newValue, oldValue). Callback would not be called if newValue and oldValue is the same.

import { useRef, createRef, useState } from 'react';
import { useCallbackRef, createCallbackRef } from 'use-callback-ref';

const Component = () => {
  const [, forceUpdate] = useState();
  // I dont need callback when ref changes
  const ref = useRef(null);

  // but sometimes - it could be what you need
  const anotherRef = useCallbackRef(null, () => forceUpdate());

  useEffect(() => {
    // now it's just possible
  }, [anotherRef.current]); // react to dom node change
};

💡 You can use useCallbackRef to convert RefObject into RefCallback, creating bridges between the old and the new code

// some old component
const onRefUpdate = (newRef) => {...}
const refObject = useCallbackRef(null, onRefUpdate);
// ...
<SomeNewComponent ref={refObject}/>

assignRef

🤔 Use case: every time you need to assign ref manually, and you dont know the shape of the ref

assignRef(ref, value) - assigns values to the ref. ref could be RefObject or RefCallback.

🚫 ref.current = value // what if it's a callback-ref?
🚫 ref(value) // but what if it's a object ref?

import {assignRef} from "use-callback-ref";
✅ assignRef(ref, value);

useTransformRef (to replace React.useImperativeHandle)

🤔 Use case: ref could be different. transformRef(ref, tranformer):Ref - return a new ref which would propagate all changes to the provided ref with applied transform

// before
const ResizableWithRef = forwardRef((props, ref) => <Resizable {...props} ref={(i) => i && ref(i.resizable)} />);

// after

const ResizableWithRef = forwardRef((props, ref) => (
  <Resizable {...props} ref={transformRef(ref, (i) => (i ? i.resizable : null))} />
));

refToCallback

refToCallback(ref: RefObject): RefCallback - for compatibility between the old and the new code. For the compatibility between RefCallback and RefObject use useCallbackRef(undefined, callback)

useMergeRefs

mergeRefs(refs: arrayOfRefs, [defaultValue]):ReactMutableRef - merges a few refs together

When developing low level UI components, it is common to have to use a local ref but also support an external one using React.forwardRef. Natively, React does not offer a way to set two refs inside the ref property. This is the goal of this small utility.

import React from 'react';
import { useMergeRefs } from 'use-callback-ref';

const MergedComponent = React.forwardRef((props, ref) => {
  const localRef = React.useRef();
  // ...
  // both localRef and ref would be populated with the `ref` to a `div`
  return <div ref={useMergeRefs([localRef, ref])} />;
});

💡 - useMergeRefs will always give you the same return, and you don't have to worry about [localRef, ref] unique every render.

mergeRefs

mergeRefs(refs: arrayOfRefs, [defaultValue]):ReactMutableRef - merges a few refs together is a non-hook based version. Will produce the new ref every run, causing the old one to unmount, and be populated with the null value.

mergeRefs are based on https://github.com/smooth-code/react-merge-refs, just exposes a RefObject, instead of a callback

mergeRefs are "safe" to use as a part of other hooks-based commands, but don't forget - it returns a new object every call.

Similar packages:

  • apply-ref - applyRefs is simular to mergeRef, applyRef is similar to assignRef
  • useForkRef - useForkRef is simular to useMergeRefs, but accepts only two arguments.
  • react-merge-refs - merge-refs is simular to useMergeRefs, but not a hook and does not provide "stable" reference.

Is it a rocket science? No, RefObject is no more than {current: ref}, and use-callback-ref is no more than getter and setter on that field.

License

MIT