Web API Cookbook

Chapter 11. Internationalization

Introduction

Modern browsers include a robust Internationalization API. This is a collection of APIs centered around language- or locale-specific tasks, such as:

• Formatting dates and times

• Formatting numbers

• Currency

• Pluralization rules

Before this API was available, you might have had to reach for a third-party library like Moment.js (for dates and times) or Numeral.js (for numbers). However, today’s browsers support many of the same use cases, and you may not need these libraries in your app anymore.

Most of these APIs use the concept of a locale, which is usually a combination of a language and a region. For example, the locale for US English is en-US, and the locale for Canadian English is en-CA. You can use them with the default locale, which is the one being used by the browser, or you can specify a particular locale to format data appropriately for your desired region.

Note

There is a new JavaScript date and time API in development called Temporal. At the time of writing, this is currently an ECMAScript proposal. It may become part of the language in the near future, but for the time being this book will cover the standard Date API.

Formatting a Date

Problem

You want to display a Date object in a format appropriate for the user’s locale.

Solution

Use Intl.DateTimeFormat to format the Date object to a string value. Create the format object with two arguments: the desired locale and an options object where you can specify ...