Convert CSV to JSON and vice versa

csv-json.js

/** @param {string} csvString * @returns {object[]} */
export function CSV2JSON(csvString) {
  const rows = csvString.split("\n");
  const header = rows[0];
  const cols = header.split(",");
  return rows
    .filter((r) => r.length !== 0)
    .slice(1)
    .map((row) => {
      const rowCols = row.split(",");
      const obj = {};
      for (const i in cols) {
        obj[cols[i]] = rowCols[i];
      }
      return obj;
    });
}

/** @param {object[]} json * @returns {string} */
export function JSON2CSV(json) {
  if (json === "string") json = JSON.parse(json);
  if (json.length === 0) return "";
  const keys = Object.keys(json[0]);
  const header = keys.join(",");
  const body = json
    .map((row) =>
      Object.values(row)
        .map((col) => {
          if (typeof col === "string" && col.includes(","))
            return String(`"${col}"`);
          return String(col);
        })
        .join(",")
    )
    .join("\n");
  return `${header}\n${body}`;
}