Function handler

core/src/utils/overlays.ts:816–819

(ev: Event)

export const onceEvent = (element: HTMLElement, eventName: string, callback: (ev: Event) => void) => {
  const handler = (ev: Event) => {
    removeEventListener(element, eventName, handler);
    callback(ev);
  };
  addEventListener(element, eventName, handler);
};