title: arrayToCSV tags: array,string,intermediate

Converts a 2D array to a comma-separated values (CSV) string.

Use Array.prototype.map() and Array.prototype.join(delimiter) to combine individual 1D arrays (rows) into strings. Use Array.prototype.join('\n') to combine all rows into a CSV string, separating each row with a newline. Omit the second argument, delimiter, to use a default delimiter of ,.

const arrayToCSV = (arr: (string | number)[][], delimiter = ",") =>
  arr
    .map((v) =>
      v
        .map((x) => (typeof x === "string" ? `"${x.replace(/"/g, '""')}"` : x))
        .join(delimiter)
    )
    .join("\n");

arrayToCSV([
  ["a", "b"],
  ["c", "d"],
]); // '"a","b"\n"c","d"'
arrayToCSV(
  [
    ["a", "b"],
    ["c", "d"],
  ],
  ";"
); // '"a";"b"\n"c";"d"'
arrayToCSV([
  ["a", '"b" great'],
  ["c", 3.1415],
]); // '"a","""b"" great"\n"c",3.1415'