Convert Array of Objects to CSV with Javascript

arrayToCsv.js

/**
 * Take an array of objects of similar structure and convert it to a CSV.
 * @source     https://halistechnology.com/2015/05/28/use-javascript-to-export-your-data-as-csv/
 * @modifiedBy sators
 * @param      {Array}  options.data            Array of data
 * @param      {String} options.columnDelimiter Column separator, defaults to ","
 * @param      {String} options.lineDelimiter   Line break, defaults to "\n"
 * @return     {String}                         CSV
 */
export default ({data = null, columnDelimiter = ",", lineDelimiter = "\n"}) => {
	let result, ctr, keys

	if (data === null || !data.length) {
		return null
	}

	keys = Object.keys(data[0])

	result = ""
	result += keys.join(columnDelimiter)
	result += lineDelimiter

	data.forEach(item => {
		ctr = 0
		keys.forEach(key => {
			if (ctr > 0) {
				result += columnDelimiter
			}

			result += typeof item[key] === "string" && item[key].includes(columnDelimiter) ? `"${item[key]}"` : item[key]
			ctr++
		})
		result += lineDelimiter
	})

	return result
}

arrayToCsv.test.js

import { expect } from "chai"

import arrayToCsv from "./arrayToCsv"

describe("arrayToCsv()", () => {
	let data
	beforeEach(() => {
		data = [{
			col1: "data1",
			col2: "data2",
			col3: 3
		}]
	})
	it("converts an aray to a CSV with the default parameters", () => {
		const expected = "col1,col2,col3\ndata1,data2,3\n"
		expect(arrayToCsv({data})).to.equal(expected)
	})
	it("returns null if no data is passed", () => {
		expect(arrayToCsv({})).to.equal(null)
		expect(arrayToCsv({data: []})).to.equal(null)
	})
	it("can use a custom column delimiter", () => {
		const expected = "col1:col2:col3\ndata1:data2:3\n"
		expect(arrayToCsv({data, columnDelimiter: ":"})).to.equal(expected)
	})
	it("can use a custom line delimiter", () => {
		const expected = "col1,col2,col3:data1,data2,3:"
		expect(arrayToCsv({data, lineDelimiter: ":"})).to.equal(expected)
	})
	it("encompases the value with quotes when it contains the columnDelimiter", () => {
		data[0].col2 = "data,2"
		const expected = "col1,col2,col3\ndata1,\"data,2\",3\n"
		expect(arrayToCsv({data})).to.equal(expected)
	})
})