export default class AssetCompiler {
    readonly sourceDir: string;
    readonly targetDir: string;
    private rollup?;
    private extensions;
    /**
     * @param sourceDir The source assets directory.
     * @param targetDir The output directory that should contain all final and public assets.
     */
    constructor(sourceDir: string, targetDir: string);
    addExtension(extension: string): void;
    compile(watch: boolean): Promise<void>;
    stopWatching(restart: boolean): Promise<void>;
}