How to Write to CSV File | JavaScript and Node.js

CSV (Comma Separated Values) is a popular file format for storing tabular data. In this article, we will discuss how to write to a CSV file using JavaScript and Node.js.

Using Node.js

Node.js is a popular runtime environment for running JavaScript on the server side. To write to a CSV file using Node.js, you can use the fs module, which provides an API for interacting with the file system.

    const fs = require('fs');

    const data = [
      { name: 'John Doe', age: 30, email: 'john@example.com' },
      { name: 'Jane Smith', age: 25, email: 'jane@example.com' }
    ];

    const csv = data.map(row => Object.values(row).join(',')).join('n');
    
    fs.writeFile('output.csv', csv, (err) => {
      if (err) throw err;
      console.log('CSV file has been saved');
    });
  

Using Browser-based JavaScript

If you want to write to a CSV file using JavaScript in a web browser, you can use the Blob and URL APIs to create and download the file.

    const data = [
      { name: 'John Doe', age: 30, email: 'john@example.com' },
      { name: 'Jane Smith', age: 25, email: 'jane@example.com' }
    ];

    const csv = data.map(row => Object.values(row).join(',')).join('n');

    const blob = new Blob([csv], { type: 'text/csv' });
    const url = URL.createObjectURL(blob);

    const a = document.createElement('a');
    a.href = url;
    a.download = 'output.csv';
    a.textContent = 'Download CSV';
    document.body.appendChild(a);
  

Conclusion

Writing to a CSV file using JavaScript is a common task, and it can be done using both Node.js on the server side and browser-based JavaScript on the client side. With the examples provided in this article, you should be able to create and download CSV files with ease.