/// <reference types="node" />
/**
*  @license
* Copyright 2022 JsData. All rights reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.

* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ==========================================================================
*/
import { CsvInputOptionsNode, CsvOutputOptionsNode } from "../../../danfojs-base/shared/types";
import DataFrame from "../core/frame";
import stream from "stream";
/**
 * Converts a function to a pipe transformer.
 * @param func The function to convert to a pipe transformer.
 * @returns A pipe transformer that applies the function to each row of object.
 * @example
 * ```
 * import { convertFunctionTotransformer } from "danfojs-node"
 *
 * const renamer = (dfRow) => {
 *    const dfModified = dfRow["Names"].map((name) => name.split(",")[0])
 *    return dfModified
 * }
 * const transformer = convertFunctionTotransformer(renamer)
 * ```
 *
*/
declare const convertFunctionTotransformer: (func: (df: DataFrame) => DataFrame) => stream.Transform;
/**
 * A pipeline transformer to stream a CSV file from local storage,
 *  transform it with custom transformer, and write to the output stream.
 * @param inputFilePath The path to the CSV file to stream from.
 * @param transformer The transformer function to apply to each row. Note that each row
 * of the CSV file is passed as a DataFrame with a single row to the transformer function, and
 * the transformer function is expected to return a transformed DataFrame.
 * @param options Configuration options for the pipeline. Includes:
 * - `outputFilePath` The local file path to write the transformed CSV file to.
 * - `customCSVStreamWriter` A custom CSV stream writer function. This is applied at the end of each transform.
 * If not provided, the default CSV stream writer is used, and this writes to local storage.
 * - `inputStreamOptions` Configuration options for the input stream. Supports all Papaparse csv reader config options.
 * - `outputStreamOptions` Configuration options for the output stream. This only applies when
 * using the default CSV stream writer. Supports all `toCSV` options.
 * @returns A promise that resolves when the pipeline is complete.
 * @example
 * ```
 * import { streamCsvTransformer } from "danfojs-node"
 *
 * const transformer = (dfRow) => {
 *   const dfModified = dfRow["Names"].map((name) => name.split(",")[0])
 *  return dfModified
 * }
 * const inputFilePath = "./data/input.csv"
 * const outputFilePath = "./data/output.csv"
 *
 * streamCsvTransformer(inputFilePath, transformer, { outputFilePath })
 * ```
*/
declare const streamCsvTransformer: (inputFilePath: string, transformer: (df: DataFrame) => DataFrame, options: {
    outputFilePath?: string | undefined;
    customCSVStreamWriter?: any;
    inputStreamOptions?: CsvInputOptionsNode | undefined;
    outputStreamOptions?: CsvOutputOptionsNode | undefined;
}) => void;
export { streamCsvTransformer, convertFunctionTotransformer };