How to convert JavaScript array to CSV?

To convert JavaScript array to CSV, we clal the map and join methods.

For instance, we write

const testArray = [
  ["name1", 2, 3],
  ["name2", 4, 5],
  ["name3", 6, 7],
  ["name4", 8, 9],
  ["name5", 10, 11],
];
const csv = testArray.map((row) => row.join(",")).join("\n");

to call testArray.map with a callback that joins the array entries into a comma separated string with row.join(",").

And then we combine the row strings into a CSV string by calling join with '\n'.