/**
 * Utility class for local filesystem operations.
 *
 * To read huge text files, consider using a line-by-line streaming approach
 * in your application code rather than using this class.
 * Chris Joakim, 2025
 */
export declare class FileUtil {
    constructor();
    /**
     *
     * @see https://nodejs.org/api/fs.html#fsaccesspath-mode-callback
     */
    fileExists(filename: string): boolean;
    /**
     * Return the current directory where this node.js process is running.
     */
    cwd(): string;
    /**
     * Return a list of files in the given directory.
     */
    listFilesInDir(dir: string): Array<string>;
    /**
     * Read the given filename and return its contents as a text string.
     */
    readTextFileSync(infile: string): string;
    /**
     * Read the given filename and return its contents an array
     * of strings, one per line.
     */
    readTextFileAsLinesSync(infile: string): Array<string>;
    /**
     * Write the given string/text content to the given filename.
     * Return true if successful, else false.
     */
    writeTextFileSync(outfile: string, data: string): boolean;
    /**
     * Read the given JSON Array file and return its parsed contents.
     * The file contents must begin and end with the '[' and ']' characters.
     */
    readJsonArrayFile(infile: string): Array<Object>;
    /**
     * Read the given JSON Array file and return its parsed contents.
     * The file contents must begin and end with the '{' and '}' characters.
     */
    readJsonObjectFile(infile: string): Object;
    deleteFile(fn: string): void;
    deleteFilesInDir(dir: string): void;
}