useImperativeHandler and how it can merge refs | Next.js | Page 1

this feels a bit magical to me. its fine since im not that experienced anyway.

but here is how i try to see useImperativeHandle like im one of the three stoodges.

im trying to create a reusable component in react19 and i want to include the fact that i may pass down ref from the parent but still able to reference an innerRef inside the component.

Here are the scenarios how a component may be used and how useImperativeHandle might help:

A ref object may be created in the parent and then passed down to a custom component,
usually it is passed directly to a DOM node like this <div ref={ref}> if you don't need custom handling.

export function Dialog({ref, ...props}: ComponentProps<"dialog">) {
  return (<div {...props} ref={ref}/>
}

Then react would internally assign the DOM node -> into -> the ref like ref.current = DOM node
and now in the parent the ref has access to DOM node
and now in the parent we can access the DOM node for example, to dialogRef.showModal() if a button is clicked (yay)

but what if we want to access the ref internally?

with useImperativeHandle, we take care of the assignment of the refs.

export function Dialog({ref, ...props}: ComponentProps<"dialog">) {
  const open = () => {...}
  const close = () => {...}
  useImperativeHandle(ref, () => ({ open, close }))
  return (<div {...props} ref={ref}/>
}

when ref object is passed down into a component,
we assign something, lets say a() and b() -> into -> the ref like ref.current = { a(), b() }
and now parent in the ref ONLY have access to DOM node, but Typescript can't flow upward so we have to change the type from <HTMLDivEelemnt> to { a() , b() }
and now parent's current ref will have access to a() b() not the DOM.
so dialogRef.showModal() will not work but dialogRef.a() would.

and now how do we work with internal refs and merging it?

export function Dialog({ref, ...props}: ComponentProps<"dialog">) {
  const internalRef = useRef<HTMLDialogElement>(null)
  useImperativeHandle(ref, () => internalRef.current!)
  return (<div {...props} ref={internalRef}/>
}

when ref object is passed down into a component,
we assign the passed down ref WITH another internal ref object.
but the passed-down-ref isn't passed to the DOM node so it isn't assigned with DOM node
instead the passed-down-ref is assigned with the internal ref object in the useImperativeHandler hook
and the internal ref object is passed to the DOM node. <div ref={internalRef}>

so its like when ref={internalRef}
internally, on render, internalRef.current = DOM node
but then due to useImperativeHandler, ref.current = internalRef.current
therefore at parent node, ref.current = DOM node.
and resulted in being able to control ref at parent AND ref at internal

This is how I understand how useImperativeHandle works.

That being said, Im still scared since react really recommends me to not use useImperativeHandle if not needed and rely on declarative approach. But then I needed the ref because <dialog>'s API relies on the HTMLDialogElement API. The changes in react19 makes it very east to work with refs and im afraid of being too comfortable with this refs

P.S forgive me if there is any english teachers reading this

#useImperativeHandler and how it can merge refs