Cookbooks
JavaScript
Chapter 10. Data Formats and Serialization
Working with CSV

JavaScript:
Working with CSV

How to:

JavaScript does not have built-in CSV parsing or stringifying functionality like it does with JSON. However, you can easily manage CSV data by using either raw JavaScript for simpler tasks or leveraging powerful libraries like PapaParse for more complex scenarios.

Basic Parsing with Raw JavaScript

To parse a simple CSV string into an array of objects:

const csv = `name,age,city
John,23,New York
Jane,28,Los Angeles`;

function parseCSV(csv) {
  const lines = csv.split("\n");
  const result = [];
  const headers = lines[0].split(",");

  for (let i = 1; i < lines.length; i++) {
    const obj = {};
    const currentline = lines[i].split(",");
    
    for (let j = 0; j < headers.length; j++) {
      obj[headers[j]] = currentline[j];
    }
    result.push(obj);
  }
  
  return result;
}

console.log(parseCSV(csv));

Output:

[
  { name: 'John', age: '23', city: 'New York' },
  { name: 'Jane', age: '28', city: 'Los Angeles' }
]

Basic Generation to CSV with Raw JavaScript

To convert an array of objects into a CSV string:

const data = [
  { name: 'John', age: 23, city: 'New York' },
  { name: 'Jane', age: 28, city: 'Los Angeles' }
];

function arrayToCSV(arr) {
  const csv = arr.map(row => 
    Object.values(row).join(',')
  ).join('\n');
  
  return csv;
}

console.log(arrayToCSV(data));

Output:

John,23,New York
Jane,28,Los Angeles

Using PapaParse for Complex CSV Tasks

For more complex scenarios, PapaParse is a robust library suitable for parsing and stringifying CSV files with options for streams, workers, and handling huge files.

Parsing CSV file or string with PapaParse:

// After adding PapaParse to your project
const Papa = require('papaparse');
const csv = `name,age,city
John,23,New York
Jane,28,Los Angeles`;

Papa.parse(csv, {
  complete: function(results) {
    console.log("Parsed:", results.data);
  }
});

Generates:

Parsed: [
  ["name", "age", "city"],
  ["John", "23", "New York"],
  ["Jane", "28", "Los Angeles"]
]

Stringifying an array to a CSV string with PapaParse:

const data = [
  { name: 'John', age: 23, city: 'New York' },
  { name: 'Jane', age: 28, city: 'Los Angeles' }
];

console.log(Papa.unparse(data));

Generate:

name,age,city
John,23,New York
Jane,28,Los Angeles

These examples illustrate basic and advanced CSV handling in JavaScript, enabling easy data exchange in web applications and beyond.

Working with JSON