Installation

formatjs is a set of libraries that help you setup internationalization in any project whether it's React or not.

Installation

npm i -S react react-intl

Minimal Application

After following the step above, you should be able to get a minimal application like this running:

import {createIntl, createIntlCache} from 'react-intl'
// Translated messages in French with matching IDs to what you declared
const messagesInFrench = {
myMessage: "Aujourd'hui, c'est le {ts, date, ::yyyyMMdd}",
}
// This is optional but highly recommended
// since it prevents memory leak
const cache = createIntlCache()
// Create the `intl` object
const intl = createIntl(
{
// Locale of the application
locale: 'fr',
// Locale of the fallback defaultMessage
defaultLocale: 'en',
messages: messagesInFrench,
},
cache
)
// Aujourd'hui, c'est le 23/07/2020
console.log(
intl.formatMessage(
{
// Matching ID as above
id: 'myMessage',
// Default Message in English
defaultMessage: 'Today is {ts, date, ::yyyyMMdd}',
},
{ts: Date.now()}
)
)
// 19,00 €
console.log(intl.formatNumber(19, {style: 'currency', currency: 'EUR'}))
tip

If you're not using React, you can use @formatjs/intl instead that has the same API. In fact, react-intl also uses @formatjs/intl

Minimal React Application

If you're using React, a minimal React application can look like this:

import * as React from 'react'
import {IntlProvider, FormattedMessage, FormattedNumber} from 'react-intl'
// Translated messages in French with matching IDs to what you declared
const messagesInFrench = {
myMessage: "Aujourd'hui, c'est le {ts, date, ::yyyyMMdd}",
}
export default function App() {
return (
<IntlProvider messages={messagesInFrench} locale="fr" defaultLocale="en">
<p>
<FormattedMessage
id="myMessage"
defaultMessage="Today is {ts, date, ::yyyyMMdd}"
values={{ts: Date.now()}}
/>
<br />
<FormattedNumber value={19} style="currency" currency="EUR" />
</p>
</IntlProvider>
)
}

Output

<p>
Aujourd'hui, c'est le 23/07/2020
<br />
19,00 €
</p>

Adding our babel-plugin/TypeScript Transformer for compilation

Our tooling supports babel, ts-loader, ts-jest, rollup-plugin-typescript2 & ttypescript for message compilation:

Babel

If you're using babel, add babel-plugin-react-intl to your dependencies:

npm i -D babel-plugin-react-intl

and add it to your babel.config.js or .babelrc:

{
"plugins": [
[
"react-intl",
{
"idInterpolationPattern": "[sha512:contenthash:base64:6]",
"extractFromFormatMessageCall": true,
"ast": true
}
]
]
}

ts-loader

npm i -D @formatjs/ts-transformer
import {transform} from '@formatjs/ts-transformer'
module.exports = {
...otherConfigs,
module: {
rules: [
{
test: /\.tsx?$/,
use: [
{
loader: 'ts-loader',
options: {
getCustomTransformers: {
before: [
transform({
overrideIdFn: '[sha512:contenthash:base64:6]',
ast: true,
}),
],
},
},
},
],
},
],
},
}

ts-jest in jest.config.js

npm i -D @formatjs/ts-transformer

Take a look at ts-jest guide on how to incorporate custom AST Transformers.

ttypescript

npm i -D @formatjs/ts-transformer
{
"compilerOptions": {
"plugins": [
{
"transform": "@formatjs/ts-transformer",
"import": "transform",
"type": "config",
"overrideIdFn": "[sha512:contenthash:base64:6]",
"ast": true
}
]
}
}

rollup-plugin-typescript2

npm i -D @formatjs/ts-transformer
// rollup.config.js
import typescript from 'rollup-plugin-typescript2'
import {transform} from '@formatjs/ts-transformer'
export default {
input: './main.ts',
plugins: [
typescript({
transformers: () => ({
before: [
transform({
overrideIdFn: '[sha512:contenthash:base64:6]',
ast: true,
}),
],
}),
}),
],
}