FormatJS
FormatJS is a modular collection of JavaScript libraries for internationalization (i18n) and localization (l10n), enabling developers to format dates, numbers, and strings in multiple languages. It provides tools like react-intl for React applications and intl-messageformat for message formatting, supporting ICU Message syntax for complex translations. It helps create globally accessible web and mobile apps by handling locale-specific formatting and pluralization rules.
Developers should learn FormatJS when building applications for international audiences, as it simplifies the process of adapting content to different languages and regions. It is particularly useful for React-based projects needing dynamic translations, date/number formatting, and plural handling, such as e-commerce sites, SaaS platforms, or any app with global users. Its modular design allows integration with various frameworks, making it a versatile choice for i18n workflows.