Function observeElement

Returns
    | {
        active: boolean;
        callback: any;
        elements: Set<any>;
        multiple: any;
        onRemove: any;
        root: any;
        selector: any;
        disconnect(): void;
    }
    | {
        active: boolean;
        callback: any;
        element: null;
        multiple: any;
        onRemove: any;
        root: any;
        selector: any;
        disconnect(): void;
    }