/**
 * Applies a diff hunk to a file or creates a new file if necessary.
 * Follows the same logic as the Python version.
 *
 * @param fname - File path to modify
 * @param content - Current content of the file, or null if file doesn't exist
 * @param hunk - The diff hunk to apply
 * @returns The new content if successful, or undefined if application fails
 */
export declare function doReplace(fname: string, content: string | null, hunk: string[]): string | undefined;
/**
 * Helper function to collapse repeated characters in a string.
 * This is the TypeScript implementation of the Python collapse_repeats function.
 *
 * @param s - String to process
 * @returns String with consecutive duplicate characters replaced by a single instance
 */
export declare function collapseRepeats(s: string): string;