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use-callback-ref

1.2.1 • Public • Published

🤙 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 hook change
  • mergeRefs - merge multiple refs together. For, actually, fork
  • transformRef - transform one ref to anther
  • refToCallback - convert RefObject to an old callback-style ref
  • assignRef - assign value to the ref, regardless of it's form

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 = (newValue) => {...}
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])} />
})

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.

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

Install

npm i use-callback-ref

DownloadsWeekly Downloads

1,008,974

Version

1.2.1

License

MIT

Unpacked Size

18.6 kB

Total Files

42

Last publish

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