astro-i18n
A TypeScript-first internationalization library for Astro.
Key features
- 🪶 Lightweight.
- 🏗️ Build-time loading.
- 🌏 Internationalized routing.
- 🔒 Type-safety and autocompletion.
- 🔧 Support for plurals, context, interpolations and formatters.
- 🚀 Built for Astro and nothing else.
Preview
Translation function
Translated routing function
Content page
Get started
Installation
npm install astro-i18n
yarn add astro-i18n
pnpm add astro-i18n
Setup
Automatic
Run the following command.
node_modules/.bin/astro-i18n install
deno run npm:astro-i18n install
Add astroI18n.init(Astro)
at the start of your page's frontmatter.
---
import { astroI18n } from "astro-i18n"
astroI18n.init(Astro)
---
<MyApp />
Go to next step.
Manual
Add astro-i18n to your astro.config
integrations.
import { defineConfig } from "astro/config"
import i18n from "astro-i18n"
export default defineConfig({ integrations: [i18n()] })
Create an astro.i18n.config
file, supported extensions are .js
, .cjs
, .mjs
, .ts
, .cts
, .mts
, .json
.
You can use the defineAstroI18nConfig
helper to get autocompletion.
import { defineAstroI18nConfig } from "astro-i18n"
export default defineAstroI18nConfig({
defaultLangCode: "en",
supportedLangCodes: [],
showDefaultLangCode: false,
translations: {},
routeTranslations: {},
})
Add the following line to src/env.d.ts
. You may get an error because the file doesn't exist yet, it's ok.
This file will contain your generated types, if you want to remove the error for now you can create a placeholder for that path.
Add the following command to your scripts.
{
"i18n:sync": "astro-i18n sync"
}
{
"i18n:sync": "deno run npm:astro-i18n sync"
}
Add astroI18n.init(Astro)
at the start of your page's frontmatter.
---
import { astroI18n } from "astro-i18n"
astroI18n.init(Astro)
---
<MyApp />
Configuration
defaultLangCode
Determines your default language.
It's en
by default.
supportedLangCodes
An array of all the supported languages that are not your defaultLangCode
.
This is an empty array by default.
showDefaultLangCode
This will control the visibility of the defaultLangCode
in the URL.
If defaultLangCode
is en
and if showDefaultLangCode
is true your index page will be /en
instead of /
.
It's false by default.
translations
Add your translations as code, or provide a file path to load them from a .json
file.
You can also add page specific translations
directly from the page's directory.
export default defineAstroI18nConfig({
defaultLangCode: "en",
supportedLangCodes: ["de"],
translations: {
en: {
my: {
translation: "A text translation".
}
},
de: "root/relative/path/to/my/german/translations.json"
},
})
routeTranslations
This works similarly to translations
, except the language's object is not nested and you don't need to provide translations for your defaultLangCode
.
You can also add your routeTranslations
directly from the page's directory.
export default defineAstroI18nConfig({
defaultLangCode: "en",
supportedLangCodes: ["fr", "it"],
routeTranslations: {
fr: {
about: "a-propos",
products: "produits",
posts: "articles",
},
it: "root/relative/path/to/my/italian/route/translations.json",
},
})
That's it
Run the following command to generate the types corresponding to your configuration and translations.
npm run i18n:sync
deno run npm:astro-i18n install
Start translating.
---
import { astroI18n, t, l } from "astro-i18n"
astroI18n.init(Astro)
---
<a href={ l("/about") }>
{ t("page.about") }
</a>
Reference
Declare your translations directly in pages
You can have your translation and your route translations sitting directly with your pages by having an i18n
folder next to them. The .json
translations files will be named after the language they cover.
You can use the special translation key "{route}"
to translate the route.
Example
src/
├── pages/
│ ├── index.astro
│ ├── i18n/
│ │ ├── en.json
│ │ └── fr.json
│ └── about/
│ ├── index.astro
│ └── i18n/
│ ├── en.json
│ └── fr.json
src/pages/about/i18n/fr.json
{
"{route}": "a-propos",
"my": {
"translation:": "Une traduction."
}
}
Variants
Variants are the way that plurals and context are handled. At the moment they support string
and number
values (you can mix them).
astro-i18n will try to find the closest match.
If there is a variantless translation key, it will be used as a default value.
- Numbers will match the closest one.
- Strings will match exact matches.
Examples
Numbers
{
"my": {
"translation": "I have nothing.",
"translation{nCars:1, nBikes:1}": "I have a car and a bike.",
"translation{nCars:2, nBikes:1}": "I have a lot of cars but only one bike.",
"translation{nCars:1, nBikes:2}": "I have only one car but a lot of bikes.",
"translation{nCars:2, nBikes:2}": "I have a lot of cars and bikes."
}
}
import { t } from "astro-i18n"
t("my.translation")
t("my.translation", { nCars: 0, nBikes: 1 })
t("my.translation", { nCars: 11, nBikes: 0 })
t("my.translation", { nCars: -7, nBikes: 5 })
t("my.translation", { nCars: 2, nBikes: 15 })
Strings
{
"my": {
"translation": "Just a normal day.",
"translation{weather:'cold'}": "It's really rainy today.",
"translation{weather:'hot'}": "It's really sunny today."
}
}
import { t } from "astro-i18n"
t("my.translation")
t("my.translation", { weather: "cold" })
t("my.translation", { weather: "hot" })
Interpolation
Interpolations allow you to insert content into a translation. The inserted content can be pre-processed by formatters.
Example
{
"my": {
"translation1": "My name is {name}.",
"translation2": "My name is {name:'Alex'}.",
"translation3": "My name is {name:'Jessica'|uppercase}.",
"translation3": "My name is {name|uppercase|lowercase}."
}
}
import { t } from "astro-i18n"
t("my.translation1", { name: "Patrick" })
t("my.translation2")
t("my.translation3")
t("my.translation3", { name: "JoHn" })
Formatters
Formatters are functions that take the inserted value (or default value if none) and return a string. If there's more than one formatter for the same interpolation they will be chained. You can add custom formatters using astroI18n.init
or astroI18n.addFormatter.
Just like the main interpolation value, formatters can also take variables that will be given at run-time through the t
function options.
Example
{
"my": {
"translation1": "It costs {amount|number(options)}.",
"translation2": "It was the {datetime|date(options)}."
}
}
import { t } from "astro-i18n"
t("my.translation1", {
amount: 50,
options: { style: "currency", currency: "EUR" },
})
t("my.translation2", {
datetime: Date.now(),
options: { dateStyle: "full" },
})
Default formatters
date
A wrapper around Intl.DateTimeFormat.
It can take a Date
, a number
or a string
as value.
Displays the year, month and days and uses the current language by default.
date(value: unknown, options: Intl.DateTimeFormatOptions = {}, langCode = astroI18n.langCode)
number
A wrapper around Intl.NumberFormat.
It can take a number
or a string
as value.
Displays the given number to the given language format by default (uses the current one if not provided).
number(value: unknown, options: Intl.NumberFormatOptions = {}, langCode = astroI18n.langCode)
API
i18n
The i18n
function is the default astro-i18n export and the astro integration function.
It can take an optional path to your astro-i18n config file, if it's not in the root.
defineAstroI18nConfig
The defineAstroI18nConfig
is an helper to give you autocompletion and type-safety when defining your astro-i18n config.
This function will extract a supported lang code (either the default one or one inside supportedLangCodes
) from the given route.
appendQueryString
A helper function to append a query string to a url/route.
astroI18n
This is where the astro-i18n run-time state resides.
The langCode
gets updated thanks to astroI18n.init
, because of this it is only usable after the function runs.
defaultLangCode
: see configuration.supportedLangCodes
: see configuration.showDefaultLangCode
: see configuration.translations
: see configuration.routeTranslations
: see configuration.init
: A function to initialize astro-i18n for the current request/page, it will set astroI18n.langCode
to the current one. You can pass an object containing your custom formatters for them to be available, e.g. astroI18n.init(Astro, { myFormatter: (value) => String(value)})
.langCode
: The langCode for the current page.langCodes
: A concatenation of defaultLangCode
and supportedLangCodes
.addTranslations
: Adds translations at runtime, see configuration.addRouteTranslations
: Adds route translations at runtime, see configuration.getFormatter
/ setFormatter
/ deleteFormatter
: Functions to manage formatters.
t
The t
function is the main function to translate, it can take up to three arguments.
path
: Your translation path, e.g. "path.to.my.translation"
.options
: (optional) An object containing all the path
's translation variant properties, interpolation and formatter arguments.langCode
: (optional) The target language, it will default to astroI18n.langCode
.
l
The l
function is a function used to get translated routes, it can take up to four arguments.
route
: The route to translate, it can take parameters, e.g. "/posts/[id]"
.params
: (optional) An object containing all the route
's params.targetLangCode
: (optional) The target language, it will default to astroI18n.langCode
.routeLangCode
: (optional) The route
langCode, the l
function will try to auto-detect it but you can override it here. If not overriden and the auto-detection fails it will default to the defaultLangCode
.
HrefLangs
An astro component that will automatically generate hreflang tags for the current page. This is used for SEO, add it to the <head>
of your page.
CLI
astro-i18n install
- Adds astro-i18n to your integrations.
- Generates an astro-i18n config file (no override).
- Generates a placeholder file for your generated types (no override).
- Links your ambient
env.d.ts
to your generated types. - Creates astro-i18n commands in your
package.json
/ deno.json
.
Option | Shortcut | Default | Description |
---|
--config | -c | Project's root | A custom path relative from the project's root where you want your astro-i18n config created. |
astro-i18n sync
- Generates translated routes (
astro-i18n sync:pages
). - Generates types for your current translations & routet translations (
astro-i18n sync:types
).
Option | Shortcut | Default | Description |
---|
--config | -c | Project's root | A custom path relative from the project's root where you want your astro-i18n config created. |
- Generates a json file containing all the pure
string
translation keys you used with the t
function in the src
directory.
Contributors