import { DataWriter, DataRecord } from '../core/interfaces';
/**
 * NDJsonWriter class for writing data records to a file in NDJSON (Newline Delimited JSON) format.
 * Each DataRecord is stringified into a JSON object and written on a new line.
 * This is efficient for large datasets as it writes records incrementally without
 * holding all of them in memory.
 */
export declare class NDJsonWriter implements DataWriter {
    private filePath;
    private outputStream;
    /**
     * Constructs a new NDJsonWriter.
     * @param filePath The path to the output file.
     */
    constructor(filePath: string);
    /**
     * Writes a single data record to the NDJSON file.
     * The record is stringified into a JSON object and appended with a newline.
     * @param record The DataRecord object to write.
     * @returns A Promise that resolves when the record has been written to the stream.
     */
    write(record: DataRecord): Promise<void>;
    /**
     * Writes all data records from an asynchronous iterable to the NDJSON file.
     * @param records An AsyncIterableIterator of DataRecord objects.
     * @returns A Promise that resolves when all records have been written.
     */
    writeAll(records: AsyncIterableIterator<DataRecord>): Promise<void>;
    /**
     * Closes the underlying write stream. This should be called when all data has been written
     * to ensure all buffered data is flushed to the file and resources are released.
     * @returns A Promise that resolves when the stream is closed.
     */
    close(): Promise<void>;
}