Internationalization plugin for Fastify. Built upon node-polyglot.
npm install fastify-i18nInternationalization plugin for Fastify. Built upon node-polyglot.
Install fastify-i18n with your favorite package manager:
``bash`
$ npm i fastify-i18nor
$ yarn add fastify-i18nor
$ pnpm i fastify-i18nor
$ bun add fastify-i18n
`js
// esm
import i18n, { defineI18n, useI18n } from 'fastify-i18n';
// cjs
const { default: i18n, defineI18n, useI18n } = require('fastify-i18n');
`
`ts
import i18n from 'fastify-i18n';
fastify.register(i18n, {
fallbackLocale: 'en',
messages: {
en: { text: 'Text' },
ja: { text: 'テキスト' },
ko: { text: '텍스트' },
zh: { text: '文字' },
},
});
/*
curl --request GET \
--url http://127.0.0.1:3000/api/i18n \
--header 'accept-language: ja'
*/
fastify.get('/api/i18n', async (req, reply) => {
return reply.send({ message: req.i18n.t('text') });
});
`
`ts
import type { FastifyInstance } from 'fastify';
import { defineI18n, useI18n } from 'fastify-i18n';
export default async (app: FastifyInstance) => {
defineI18n(app, {
en: { hello: 'Hello, World!' },
ja: { hello: 'こんにちは世界！' },
ko: { hello: '안녕하세요, 월드입니다!' },
zh: { hello: '你好，世界！' },
});
/*
curl --request GET \
--url http://127.0.0.1:3000/api/hello-world \
--header 'accept-language: ja'
*/
app.get('/hello-world', async (req, reply) => {
const i18n = useI18n(req);
return reply.send({
// global scope
text: req.i18n.t('text'),
// local scope
hello: i18n.t('hello'),
});
});
};
`
#### xx-XX to xx
`ts`
fastify.register(i18n, {
fallbackLocale: 'en',
messages: {
en: { text: 'Text' },
ja: { text: 'テキスト' },
},
});
`sh`
$ curl --request GET \
--url http://127.0.0.1:3000/api/i18n \
--header 'Accept-Language: ja-JP'Output: { text: 'テキスト' } (ja)
#### xx to xx-XX
`ts`
fastify.register(i18n, {
fallbackLocale: 'en',
messages: {
'en-US': { text: 'Text' },
'ja-JP': { text: 'テキスト' },
},
});
`sh`
$ curl --request GET \
--url http://127.0.0.1:3000/api/i18n \
--header 'Accept-Language: ja'Output: { text: 'テキスト' } (ja-JP)
#### Priority
`ts`
fastify.register(i18n, {
fallbackLocale: 'en',
messages: {
'en-US': { text: 'Text' },
'zh-CN': { text: '文本' },
'zh-TW': { text: '文字' },
},
});
`sh`
$ curl --request GET \
--url http://127.0.0.1:3000/api/i18n \
--header 'Accept-Language: zh'Output: { text: '文本' } (zh-CN)
`ts`
fastify.register(i18n, {
fallbackLocale: 'en',
messages: {
'en-US': { text: 'Text' },
'zh-TW': { text: '文字' },
'zh-CN': { text: '文本' },
},
});
`sh`
$ curl --request GET \
--url http://127.0.0.1:3000/api/i18n \
--header 'Accept-Language: zh'Output: { text: '文字' } (zh-TW)
`ts`
// global
fastify.register(i18n, {
fallbackLocale: 'en-US',
messages: import.meta.glob(['~/locales/*.ts'], { eager: true }),
});
`ts`
// local scope
defineI18n(app, import.meta.glob(['./locales/*.ts'], { eager: true }));
This guide is intended to help with migration from fastify-i18n v1 to v2.
V2 no longer distinguishes between scopes; each scope's language will override the previous layer's key with the same scope. So, useI18n is no longer needed; you can now access the instance of node-polyglot from fastify.i18n or request.i18n.
`diff
app.get('/hello-world', async (req, reply) => {
- const i18n = useI18n(req);
return reply.send({
// global scope
text: req.i18n.t('text'),
// local scope
- hello: i18n.t('hello'),
+ hello: req.i18n.t('hello'),
});
});
`
Please note that i18n must be registered before your routes, otherwise the global scope will trigger only at the last layer unless you require it.
`ts``
fastify.register(i18n);
fastify.register(router);
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