data-formatters

Utility library for formatting numbers, currency, percentages, dates, time, bytes, and text using modern Intl APIs. This project provides small, reusable helpers to standardize value formatting in frontend applications.

Features

• Currency formatting
• Compact currency formatting
• Number formatting
• Compact numbers
• Percent formatting
• Compact percent formatting
• Date formatting
• Date/time formatting
• Relative time formatting
• Duration formatting
• Bytes formatting
• Name normalization (Title Case)
• Locale support (Intl)
• Lightweight and dependency-free

Installation

npm install data-formatters

or

yarn add data-formatters

Usage

import {
  formatBytes,
  formatCurrency,
  formatDate,
  formatDateTime,
  formatDuration,
  formatCompactCurrency,
  formatNumber,
  formatCompactNumber,
  formatPercent,
  formatCompactPercent,
  formatName,
  formatRelativeTime
} from "data-formatters"

Currency

formatCurrency(1200, {
  currency: "USD",
  locale: "en-US"
})

Result:

$1,200.00

Compact Currency

formatCompactCurrency(1200000, {
  currency: "USD",
  locale: "en-US"
})

Result:

$1.2M

Numbers

formatNumber(1200, { locale: "en-US" })

Result:

1,200

Compact Numbers

formatCompactNumber(1500, { locale: "en-US" })

Result:

1.5K

Percent

formatPercent(0.25, { locale: "en-US" })

Result:

25%

Compact Percent

formatCompactPercent(0.1234, { locale: "en-US" })

Result:

12.3%

Name Formatting

formatName("victor hugo lima")

Result:

Victor Hugo Lima

Bytes

formatBytes(1536)

Result:

1.5 KB

Date

formatDate("2026-03-09T00:00:00Z", {
  locale: "en-US",
  timeZone: "UTC"
})

Result:

03/09/2026

DateTime

formatDateTime("2026-03-09T14:30:00Z", {
  locale: "en-US",
  timeZone: "UTC",
  dateStyle: "medium",
  timeStyle: "short"
})

Result:

Mar 9, 2026, 2:30 PM

Duration

formatDuration(3665)

Result:

1h 1m 5s

Relative Time

formatRelativeTime(-1, "day", "en-US")

Result:

yesterday

Locale Support

The library uses the native Intl API, so formatting behavior depends on the provided locale. Examples: | Locale | Number Example | | ------- | -------------- | | en-US | 1,000 | | pt-BR | 1.000 | | de-DE | 1.000 |

Testing

Tests are written using Vitest. Run locally:

npm test

Run in watch mode:

npm run test:watch

Development

Clone the repository:

git clone https://github.com/vhlima1008/data-formatters.git

Install dependencies:

npm install

Build:

npm run build

Contributing

Contributions are welcome! Steps:

1. Fork the repository
2. Create a branch

git checkout -b feature/my-feature

3. Commit your changes
4. Push the branch
5. Open a Pull Request

License

Distributed under the MIT License. See LICENSE for more information.

Author

Victor Hugo Lima Monteiro GitHub: https://github.com/vhlima1008