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

TypeScript:
Working with CSV

How to:

In TypeScript, you can work with CSV files through native code or by leveraging third-party libraries like csv-parser for reading and csv-writer for writing CSV files.

Reading CSV with csv-parser

First, install csv-parser via npm:

npm install csv-parser

Then, read a CSV file like so:

import fs from 'fs';
import csv from 'csv-parser';

const results = [];

fs.createReadStream('data.csv')
  .pipe(csv())
  .on('data', (data) => results.push(data))
  .on('end', () => {
    console.log(results);
    // Output: Array of objects, each representing a row in the CSV
  });

Assuming data.csv contains:

name,age
Alice,30
Bob,25

The output will be:

[ { name: 'Alice', age: '30' }, { name: 'Bob', age: '25' } ]

Writing CSV with csv-writer

To write to a CSV file, first install csv-writer:

npm install csv-writer

Then, use it as follows:

import { createObjectCsvWriter as createCsvWriter } from 'csv-writer';

const csvWriter = createCsvWriter({
  path: 'out.csv',
  header: [
    {id: 'name', title: 'NAME'},
    {id: 'age', title: 'AGE'}
  ]
});

const data = [
  { name: 'Alice', age: 30 },
  { name: 'Bob', age: 25 }
];

csvWriter
  .writeRecords(data)
  .then(() => console.log('The CSV file was written successfully'));

This code writes the following to out.csv:

NAME,AGE
Alice,30
Bob,25

These examples show how to integrate CSV processing in your TypeScript projects efficiently, whether it’s reading data for analysis or persisting application data externally.

Working with JSON