# Formatjs

> id: basic-internationalization-principles

## Pages

- [Basic Internationalization Principles](core-concepts-basic-internationalization-principles.md): Internationalized software supports the languages and cultural customs of people throughout the world. The Web reache...
- [Installation](getting-started-installation.md): formatjs is a set of libraries that help you setup internationalization in any project whether it's React or not.
- [Message Declaration](getting-started-message-declaration.md): While you can declare your messages using only`id`s, we highly recommend declaring`defaultMessage`s inline along wi...
- [Message Extraction](getting-started-message-extraction.md): Now that you've declared some messages, it's time to extract them.
- [Runtime Requirements](guides-runtime-requirements.md): :::info Browser Support
- [Intl MessageFormat](intl-messageformat.md): Formats ICU Message strings with number, date, plural, and select placeholders to create localized messages.
- [Core FormatJS Intl](intl.md): This library contains core intl API that is used by`react-intl`.
- [FormatJS Documentation](main-readme.md): This repository is the home of [FormatJS](http://formatjs.github.io/) and related libraries.
- [Intl.DateTimeFormat (ESNext)](polyfills-intl-datetimeformat.md): A spec-compliant polyfill for Intl.DateTimeFormat fully tested by the [official ECMAScript Conformance test suite](ht...
- [Intl.DisplayNames](polyfills-intl-displaynames.md): A polyfill for [`Intl.DisplayNames`](https://tc39.es/proposal-intl-displaynames).
- [Intl.getCanonicalLocales](polyfills-intl-getcanonicallocales.md): A spec-compliant polyfill/ponyfill for`Intl.getCanonicalLocales`tested by the [official ECMAScript Conformance test...
- [Intl.ListFormat](polyfills-intl-listformat.md): A spec-compliant polyfill for Intl.ListFormat fully tested by the [official ECMAScript Conformance test suite](https:...
- [Intl.Locale](polyfills-intl-locale.md): A spec-compliant polyfill/ponyfill for Intl.Locale tested by the [official ECMAScript Conformance test suite](https:/...
- [Intl.NumberFormat (ESNext)](polyfills-intl-numberformat.md): A polyfill for ESNext [`Intl.NumberFormat`][numberformat] and [`Number.prototype.toLocaleString`][tolocalestring].
- [Intl.PluralRules](polyfills-intl-pluralrules.md): A spec-compliant polyfill for [`Intl.PluralRules`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/...
- [Intl.RelativeTimeFormat](polyfills-intl-relativetimeformat.md): A spec-compliant polyfill for Intl.RelativeTimeFormat fully tested by the [official ECMAScript Conformance test suite...
- [Polyfills](polyfills.md): One of our goals is to provide developers with access to newest ECMA-402 Intl APIs. Therefore, FormatJS suite also pr...
- [Imperative API](react-intl-api.md): There are a few API layers that React Intl provides and is built on. When using React Intl you'll be interacting with...
- [Components](react-intl-components.md): React Intl has a set of React components that provide a declarative way to setup an i18n context and format dates, nu...
- [CLI](tooling-cli.md): import Tabs from '@theme/Tabs'
- [eslint-plugin-formatjs](tooling-linter.md): This eslint plugin allows you to enforce certain rules in your ICU message.
- [swc-plugin](tooling-swc-plugin.md): This has been migrated over to the swc repo itself. You can find the plugin [here](https://www.npmjs.com/package/@swc...
- [ts-transformer](tooling-ts-transformer.md): Process string messages for translation from modules that use react-intl, specifically: