type ChangeCallback = () => void;
export declare class FileWatcher {
    private callbacks;
    private handles;
    private lastEvents;
    private readonly dedupeMs;
    /**
     * Start watching `projectRoot` recursively.
     * Falls back to per-directory watching on platforms that don't support recursive mode.
     */
    start(projectRoot: string): void;
    /**
     * Update the watched directory set based on esbuild metafile inputs.
     * Adds watchers for any new parent directories not yet watched.
     */
    updateFromMetafile(watchedFiles: string[]): void;
    onChange(cb: ChangeCallback): void;
    close(): void;
    private onEvent;
}
export {};