CSV formater

csv-formatter.mjs

const reorderFields = headers => row => headers.map(key => row[key]);
const rowFormatter = row =>
  row.map(v => `"${String(v).replaceAll(`"`, `""`)}"`).join(",");
const arrayToCsv = data => data.map(rowFormatter).join("\r\n");

export function writeToString(rows, options) {
  const { headers, transform = x => x } = options;
  const data = rows.map(transform).map(reorderFields(headers));
  return arrayToCsv([headers].concat(data));
}

output.csv

usage.mjs

import { writeToString } from "./csv-formatter.mjs";

const headers = ["id", "title", "price"];
const transform = x => Object.assign({}, x, { price: x.price ?? "$0" });
const dataset = [
  { title: "Foo", id: 1, price: "$20" },
  { price: null, title: "Bar", id: 2 },
];

console.log(writeToString(dataset, { headers, transform }));