svelte-box playground
Two reactive containers, same surface. Pick one to see it run.
/box
Proxy-backed. Transparent property forwarding (box.foo reads the inner object),
callable when wrapping a function, instanceof Box through subclasses.
/fastbox
Plain class, no proxy. Same .value reactivity, same helpers and type guards. Faster
to construct, no transparent forwarding. Reach inner properties through .value.