useAnimatedAutoHeight

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Installation

useAnimatedAutoHeight returns a callback ref. Attach it to an element and, while enabled, the hook watches that element with a ResizeObserver and animates its height between measured sizes whenever the content changes — no fixed pixel values or manual measuring required. It ignores the height echoes it sets itself during an animation, so it won't fight its own updates.

Because the ref is state-backed, the effect re-runs once the node attaches — which makes it safe to use on elements that mount lazily inside a portal.

Usage

import { useAnimatedAutoHeight } from "@/hooks/use-animated-auto-height";

function ExpandingPanel({ open }: { open: boolean }) {
  // `enabled` guards the animation — e.g. disable it while the panel is closed.
  const setNode = useAnimatedAutoHeight<HTMLDivElement>(open);

  return (
    <div ref={setNode} className="overflow-hidden">
      {open ? <TallContent /> : null}
    </div>
  );
}

API

useAnimatedAutoHeight<T>(enabled)

Returns (node: T \| null) => void — a callback ref to attach to the element whose height should animate.