svelte/src/internal/client/dom/elements/bindings/document.js

Cybernetically enhanced web apps

import { listen } from './shared.js';

/**
 * @param {(activeElement: Element | null) => void} update
 * @returns {void}
 */
export function bind_active_element(update) {
	listen(document, ['focusin', 'focusout'], (event) => {
		if (event && event.type === 'focusout' && /** @type {FocusEvent} */ (event).relatedTarget) {
			// The tests still pass if we remove this, because of JSDOM limitations, but it is necessary
			// to avoid temporarily resetting to `document.body`
			return;
		}

		update(document.activeElement);
	});
}