export type ChangeHandler = (changedFiles: string[]) => void;
export type ErrorHandler = (err: Error) => void;
export declare class FileWatcher {
    private rootPath;
    private onChange;
    private watchers;
    private watchedDirs;
    private watchedDirInodes;
    private pendingFiles;
    private flushTimer;
    private debounceMs;
    private onError;
    constructor(rootPath: string, onChange: ChangeHandler, debounceMs?: number, onError?: ErrorHandler);
    start(): Promise<void>;
    stop(): void;
    private scheduleFlush;
    private watchDir;
    /**
     * Attach a watcher to a directory created after start(). Called from the
     * per-directory change callback with every event path; stats the path and
     * only recurses when it is a genuinely new, watchable directory.
     */
    private watchNewDir;
    /**
     * Forget a deleted directory and everything watched beneath it. fs.watch
     * emits no per-descendant events on a recursive delete, so the whole
     * prefix must be purged here for a recreate to re-watch the full subtree.
     */
    private unwatchSubtree;
}