export function observable(store) {
	const subscribers = new Set();

	const accessor = function _observable(newVal) {
		if (newVal !== undefined && store !== newVal) {
			store = newVal;
			subscribers.forEach(s => s(store));
		}
		return store;
	};

	accessor.subscribe = accessor._d = fn => {
		subscribers.add(fn);
		return () => subscribers.delete(fn);
	};

	accessor.unsubscribeAll = () => subscribers.clear();

	return accessor;
}