Intl.js

Format 🔢 numbers, 💱 currency values, 📅 dates, and 🕘 times for any locale with the ECMAScript Internationalization API.

Table of contents

• Introduction
• Installation
• Usage
• API reference
• Code of Conduct
• About SumUp

Introduction

@sumup-oss/intl is a light abstraction layer on top of the ECMAScript Internationalization API. In addition to a simplified API, it offers the following benefits:

Performance

Creating instances of Intl.* formatters is an expensive operation. @sumup-oss/intl solves this by memoizing the Intl formatters with a cache key based on the arguments passed to the constructor.

Compatibility

@sumup-oss/intl works in modern browsers as well as server runtimes with support for the Intl APIs (such as Node 10+[^1]). When the Intl APIs aren't (fully) available, @sumup-oss/intl tries to gracefully degrade. Please refer to the API reference to learn how certain functions behave when the runtime doesn't support the necessary APIs. If you need to support legacy browsers, consider including polyfills.

@sumup-oss/intl integrates temporal-polyfill to support formatting Temporal date-time objects.

[^1]: Node supports the Intl APIs since v8, however, it includes only the English localizations up to v12. Node v13 and above support all locales. If you're unable to use Node v13+, you can either include polyfills or use a custom Node build.

Installation

@sumup-oss/intl can be installed as a dependency via the npm package manager. The temporal-polyfill package is a required peer dependency.

npm install @sumup-oss/intl temporal-polyfill

@sumup-oss/intl requires Node v10+.

Usage

The functions exported by @sumup-oss/intl share a similar interface such as the common locales, options, and currency arguments. These are passed on almost unchanged to the Intl.* constructors and thus support the same values. If the locales argument is not provided or is undefined, the runtime's default locale is used. Please refer to the MDN documentation for more details.

Each type of data can be formatted with three increasingly advanced functions:

1. The format* functions return the formatted value as a string and cover the most common use cases.
2. The format*ToParts functions return an array of objects representing the value in parts that can be used for custom locale-aware formatting. For example, part of the formatted value could be rendered in bold.
3. The resolve*Format functions return an object with properties reflecting the locale and collation options computed during initialization of the object. These options can be passed to other functions or libraries to format values, for example react-number-format.

API reference

Number Functions

• formatNumber
• formatNumberToParts
• resolveNumberFormat

Currency Functions

• formatCurrency
• formatCurrencyToParts
• resolveCurrencyFormat

Date & Time Functions

• formatDate
• formatTime
• formatDateTime
• formatDateTimeToParts
• resolveDateTimeFormat

Variables

• CURRENCIES
• isNumberFormatSupported
• isNumberFormatToPartsSupported
• isDateTimeFormatSupported
• isDateTimeFormatToPartsSupported

Code of Conduct

We want to foster an inclusive and friendly community around our Open Source efforts. Like all SumUp Open Source projects, this project follows the Contributor Covenant Code of Conduct. Please, read it and follow it.

If you feel another member of the community violated our CoC or you are experiencing problems participating in our community because of another individual's behavior, please get in touch with our maintainers. We will enforce the CoC.

Maintainers

• Connor Bär

About SumUp

SumUp is a mobile point-of-sale provider. It is our mission to make easy and fast card payments a reality across the entire world. You can pay with SumUp in more than 30 countries, already. Our engineers work in Berlin, Cologne, Sofia, and Sāo Paulo. They write code in TypeScript, Swift, Ruby, Go, Java, Erlang, Elixir, and more.

Want to come work with us? Head to our careers page to find out more.