Rocket.Chat/app/ui/client/lib/menu.js

import _ from 'underscore';

import { menu } from '../../../ui-utils';

window.addEventListener('resize', _.debounce((() => {
	let lastState = window.matchMedia('(min-width: 780px)').matches ? 'mini' : 'large';
	menu.close();
	return () => {
		const futureState = window.matchMedia('(min-width: 780px)').matches ? 'mini' : 'large';
		if (lastState !== futureState) {
			lastState = futureState;
			menu.close();
		}
	};
})(), 100));