🤙 use-callback-ref 📞

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

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:

• https://dev.to/thekashey/the-same-useref-but-it-will-callback-8bo

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.

1import { useRef, createRef, useState } from 'react';
2import { useCallbackRef, createCallbackRef } from 'use-callback-ref';
3
4const Component = () => {
5  const [, forceUpdate] = useState();
6  // I dont need callback when ref changes
7  const ref = useRef(null);
8
9  // but sometimes - it could be what you need
10  const anotherRef = useCallbackRef(null, () => forceUpdate());
11
12  useEffect(() => {
13    // now it's just possible
14  }, [anotherRef.current]); // react to dom node change
15};

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

1// some old component
2const onRefUpdate = (newRef) => {...}
3const refObject = useCallbackRef(null, onRefUpdate);
4// ...
5<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

1// before
2const ResizableWithRef = forwardRef((props, ref) => <Resizable {...props} ref={(i) => i && ref(i.resizable)} />);
3
4// after
5
6const ResizableWithRef = forwardRef((props, ref) => (
7  <Resizable {...props} ref={transformRef(ref, (i) => (i ? i.resizable : null))} />
8));

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.

1import React from 'react';
2import { useMergeRefs } from 'use-callback-ref';
3
4const MergedComponent = React.forwardRef((props, ref) => {
5  const localRef = React.useRef();
6  // ...
7  // both localRef and ref would be populated with the `ref` to a `div`
8  return <div ref={useMergeRefs([localRef, ref])} />;
9});

💡 - 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