export const on = function ( element: Element | HTMLElement | Document | Window, event: string, handler: EventListenerOrEventListenerObject, useCapture = false ): void { if (element && event && handler) { element.addEventListener(event, handler, useCapture); } }; export const off = function ( element: Element | HTMLElement | Document | Window, event: string, handler: EventListenerOrEventListenerObject, useCapture = false ): void { if (element && event && handler) { element.removeEventListener(event, handler, useCapture); } };