How to export CSV using csv module in NodeJS

The csv module in Node.js is a versatile library that provides comprehensive functionality for parsing and writing CSV files. It offers features like support for various delimiters, encoding, and streaming capabilities, making it suitable for handling both small and large datasets efficiently.

Here’s a detailed guide on how to use the csv module to write CSV files in Node.js.

Table of Contents

• Step 1: Install the csv Module
• Step 2: Write CSV Files Using csv-stringify
• Advance: Using csv Module for Streaming Data
• Conclusion

Step 1: Install the csv Module

First, you need to install the csv module using npm. This package includes multiple utilities, including csv-stringify for writing CSV data.

npm install csv

yarn add csv

Step 2: Write CSV Files Using csv-stringify

The csv-stringify utility from the csv module is specifically designed for converting data into CSV format. It allows you to write data to a CSV file easily.

Here’s a simple example to demonstrate writing a CSV file using the csv module:

import { stringify } from "csv"
import fs from "fs"
import util from "util"

const main = async () => {
  // Sample data to be written to CSV
  const records = [
    { name: "John Doe", age: 30, email: "[email protected]" },
    { name: "Jane Smith", age: 25, email: "[email protected]" },
    { name: "Sam Brown", age: 22, email: "[email protected]" },
  ]

  // Create a writable stream for the CSV file
  const writableStream = fs.createWriteStream("./output.csv")

  // Use the stringify function from csv module
  const output = await util.promisify(stringify)(records, { header: true })

  // Write to the file
  writableStream.write(output, "utf8", () => {
    console.log("CSV file was written successfully")
  })
}

main()

Advance: Using csv Module for Streaming Data

When dealing with large datasets, streaming is a more efficient way to write CSV files. The csv module supports streaming through the Stringifier class, allowing you to write data in chunks.

Here’s how you can write CSV data using streams:

import { stringify } from "csv"
import fs from "fs"

// Sample data to be written to CSV
const data = [
  { name: "John Doe", age: 30, email: "[email protected]" },
  { name: "Jane Smith", age: 25, email: "[email protected]" },
  { name: "Sam Brown", age: 22, email: "[email protected]" },
]

// Define the columns for the CSV
const columns = ["name", "age", "email"]

// Create a write stream for the output file
const writeStream = fs.createWriteStream("./output.csv")

// Create a CSV stringifier instance
const stringifier = stringify({ header: true, columns: columns })

// Pipe the stringifier output to the write stream
stringifier.pipe(writeStream)

// Write each record to the stringifier
data.forEach((record) => stringifier.write(record))

// End the stringifier to finalize the file
stringifier.end(() => {
  console.log("CSV file was written successfully with streaming")
})

Conclusion

The csv module in Node.js offers a flexible and efficient way to write CSV files, whether you are handling small datasets or large streaming data. By utilizing its various options and configurations, you can customize the CSV writing process to suit your specific needs. Whether you’re writing simple files or dealing with complex data structures, the csv module provides the tools you need to get the job done.