const listeners = new WeakMap();
export function observe(el) {
    const keys = ['Tab', 'ArrowUp', 'ArrowDown', 'ArrowLeft', 'ArrowRight', 'Home', 'End', 'PageDown', 'PageUp'];
    const is = (event) => {
        if (keys.includes(event.key)) {
            el.classList.add('focus-visible');
        }
    };
    const isNot = () => el.classList.remove('focus-visible');
    listeners.set(el, { is, isNot });
    el.addEventListener('keydown', is);
    el.addEventListener('keyup', is);
    el.addEventListener('mousedown', isNot);
    el.addEventListener('mousedown', isNot);
}
export function unobserve(el) {
    const { is, isNot } = listeners.get(el);
    el.classList.remove('focus-visible');
    el.removeEventListener('keydown', is);
    el.removeEventListener('keyup', is);
    el.removeEventListener('mousedown', isNot);
    el.removeEventListener('mousedown', isNot);
}
export const focusVisible = {
    observe,
    unobserve
};