Dynamic Island

1"use client";
2// beui.dev/components/blocks/dynamic-island
3 
4import { AnimatePresence, motion, useReducedMotion } from "motion/react";
5import {
6  createContext,
7  useContext,
8  useEffect,
9  useLayoutEffect,
10  useMemo,
11  useRef,
12  useState,
13  type ReactNode,
14} from "react";
15import { EASE_OUT } from "@/lib/ease";
16import { cn } from "@/lib/utils";
17 
18type IslandContextValue = {
19  view: string | null;
20};
21 
22const IslandContext = createContext<IslandContextValue | null>(null);
23 
24// Shell physics in Apple's duration/bounce form one long perceptual glide with barely-there bounce, identical in
25// both directions. The shell animates real width/height (not transforms), so
26// slots are never scale-distorted.
27const SHELL_SPRING = {
28  type: "spring",
29  duration: 0.8,
30  bounce: 0.2,
31} as const;
32 
33// Content gets a touch more life than the shell.
34const CONTENT_SPRING = {
35  type: "spring",
36  duration: 0.8,
37  bounce: 0.35,
38} as const;
39 
40// Constant radius — never animated. The browser clamps it to half the shell
41// height, so the pill-to-rounded-rect morph falls out of the resize for free
42// with zero chance of corner glitches.
43const RADIUS = 32;
44 
45// iPhone pill dimensions. Also the shell's pre-measure animate target: if the
46// first commit already has a view active (e.g. a click replayed after
47// hydration), the shell blooms from the pill instead of rendering expanded
48// with no animation. Lives in `animate`, not `initial`, so server and client
49// markup agree.
50const PILL_WIDTH = 126;
51const PILL_HEIGHT = 37;
52 
53/** Tracks the natural size of the content so the shell can spring to it. */
54function useContentSize() {
55  const ref = useRef<HTMLDivElement | null>(null);
56  const [size, setSize] = useState<{ width: number; height: number } | null>(
57    null,
58  );
59 
60  // Synchronous mount measure: the shell must own explicit dimensions before
61  // the first interaction. ResizeObserver fires async after mount — a quick
62  // first press could beat it, leaving the shell auto-sized so the view
63  // snapped open instead of springing.
64  useLayoutEffect(() => {
65    const el = ref.current;
66    if (!el) return;
67    setSize({ width: el.offsetWidth, height: el.offsetHeight });
68  }, []);
69 
70  useEffect(() => {
71    const el = ref.current;
72    if (!el || typeof ResizeObserver === "undefined") return;
73    const observer = new ResizeObserver(() => {
74      setSize({ width: el.offsetWidth, height: el.offsetHeight });
75    });
76    observer.observe(el);
77    return () => observer.disconnect();
78  }, []);
79 
80// … truncated