Javascript function to convert a CSV list into list of JSON objects

CsvToJson.js

const mapCsvToJson = (csv, delimiter) => {
    const lines = csv.split("\n");
    let dataArray = [];
    let keys = [];

    for (i = 0; i < lines.length; i++) {
        const line = lines[i];
        const data = line.split(delimiter);

        if (i === 0) {
            keys = data;
        } else {
            let item = {};
            for (x = 0; x < data.length; x++) {
                item = {
                    ...item,
                    [keys[x]]: data[x],
                };
            }
            dataArray.push(item);
        }
    }

    return dataArray;
};


// use case 
const csv = "fname;age\nAnders;34\nBrian;35\nCasper;35";
const delimiter = ";";
const list = mapCsvToJson(csv, delimiter)
/* will produce:
[
  {
    "fname": "Anders",
    "age": 34
  },
  {
    "fname": "Brian",
    "age": 35
  },
  {
    "fname": "Casper",
    "age": 35
  }
]
*/

And the reverse (single level) converter from JSON to CSV:

const JsonListToCsv = (arr, delimiter = ";") => {
    let header = [];
    let rows = [];

    for (i = 0; i < arr.length; i++) {
        if (i === 0) {
            header = Object.keys(arr[i]);
        } else {
            const row = Object.values(arr[i]).join(delimiter);
            rows.push(row);
        }
    }

    const csv = header.join(delimiter) + "\n" + rows.join("\n");

    return csv;
};