type LoaderCallbackFn = () => void;
type LoaderErrorCallbackFn = (error: Error) => void;
interface QueuedCallbacks {
    cb?: LoaderCallbackFn;
    errCb?: LoaderErrorCallbackFn;
}
/**
 * A dead simple CSS and JS lazy loader
 * The file will only be loaded once (identified by its URL)
 */
declare class Loader {
    requestedJSFiles_: string[];
    loadedJSFiles_: string[];
    callbackQueue_: Record<string, QueuedCallbacks[]>;
    requestedCSSFiles_: string[];
    constructor();
    reset(): void;
    loadJS(src: string, cb?: LoaderCallbackFn, errCb?: LoaderErrorCallbackFn, crossorigin?: boolean): void;
    loadCSS(href: string): HTMLLinkElement | null;
}
declare const loader: Loader;
export default loader;