Function $toCSV

src/danfojs-base/io/node/io.csv.ts:293–325

(df: NDframe | DataFrame | Series, options?: CsvOutputOptionsNode)

 * ```
 */
const $toCSV = (df: NDframe | DataFrame | Series, options?: CsvOutputOptionsNode): string | void => {
  let { filePath, sep, header } = { sep: ",", header: true, filePath: undefined, ...options }

  if (df.$isSeries) {
    const csv = df.values.join(sep);

    if (filePath !== undefined) {
      if (!(filePath.endsWith(".csv"))) {
        filePath = filePath + ".csv"
      }
      fs.writeFileSync(filePath, csv, "utf8")
    } else {
      return csv;
    }
  } else {
    const rows = df.values as ArrayType2D
    let csvStr = header === true ? `${df.columns.join(sep)}\n` : ""

    for (let i = 0; i < rows.length; i++) {
      const row = `${rows[i].join(sep)}\n`;
      csvStr += row;
    }

    if (filePath !== undefined) {
      if (!(filePath.endsWith(".csv"))) {
        filePath = filePath + ".csv"
      }
      fs.writeFileSync(filePath, csvStr, "utf8")
    } else {
      return csvStr;
    }
  }
};


/**