Transifex Native SDK: React i18n

React component for localizing React application using Transifex Native.

Related packages:

• @transifex/native
• @transifex/cli

Learn more about Transifex Native in the Transifex Developer Hub.

How it works

Step1: Create a Transifex Native project in Transifex.

Step2: Grab credentials.

Step3: Internationalize the code using the SDK.

Step4: Push source phrases using the @transifex/cli tool.

Step5: Translate the app using over-the-air updates.

No translation files required.

Upgrade to v2

If you are upgrading from the 1.x.x version, please read this migration guide, as there are breaking changes in place.

Install

Install the library and its dependencies using:

npm install @transifex/native @transifex/react --save

Usage

T Component

import React from 'react';

import { T } from '@transifex/react';

function Example() {
  return (
    <div>
      <T _str="Hello world" />
      <T _str="Hello {username}" username={user} />
    </div>
  );
}

Available optional props:

| Prop | Type | Description | |------------|--------|---------------------------------------------| | _context | String | String context, affects key generation | | _key | String | Custom string key | | _comment | String | Developer comment | | _charlimit | Number | Character limit instruction for translators | | _tags | String | Comma separated list of tags |

The T-component can accept React elements as properties and they will be rendered properly, ie this would be possible:

<T
  _str="A {button} and a {bold} walk into a bar"
  button={<button><T _str="button" /></button>}
  bold={<b><T _str="bold" /></b>} />

This will render like this in English:

A <button>button</button> and a <b>bold</b> walk into a bar

And like this in Greek:

Ένα <button>κουμπί</button> και ένα <b>βαρύ</b> μπαίνουν σε ένα μπαρ

Assuming the translations look like this:

| source | translation | |-----------------------------------------|--------------------------------------------------| | A {button} and a {bold} walk into a bar | Ένα {button} και ένα {bold} μπαίνουν σε ένα μπαρ | | button | κουμπί | | bold | βαρύ |

The main thing to keep in mind is that the _str property to the T-component must always be a valid ICU messageformat template.

UT Component

import React from 'react';

import { UT } from '@transifex/react';

function Example () {
  return (
    <div>
      <UT _str="Hello <b>{username}</b>" username={user} />
      <p>
        <UT _str="Hello <b>{username}</b>" _inline username={user} />
      </p>
    </div>
  )
}

UT has the same behaviour as T, but renders source string as HTML inside a div tag.

Available optional props: All the options of T plus:

| Prop | Type | Description | |---------|---------|-------------------------------------------------| | _inline | Boolean | Wrap translation in span |

Note: If you supply React elements as properties to the UT component, it will misbehave by rendering [object Object]. Only use React elements as properties with the T component.

useT hook

Makes the current component re-render when a language change is detected and returns a t-function you can use to translate strings programmatically.

You will most likely prefer to use the T or UT components over this, unless for some reason you want to have the translation output in a variable for manipulation.

import React from 'react';

import { useT } from '@transifex/react';

function Capitalized() {
  const t = useT();
  const message = t('Hello world');
  return <span>{message.toUpperCase()}</span>;
}

Optionally useT can take as param a custom Native Instance:

import { useT } from '@transifex/react';
import { createNativeInstance } from '@transifex/native';

const customTX = createNativeInstance({
  token: 'token',
  secret: 'secret',
});

function Component() {
  const t = useT(customTX);
  // ...
}

useLanguages hook

Returns a state variable that will eventually hold the supported languages of the application. Makes an asynchronous call to the CDS.

import React from 'react';
import { useLanguages } from '@transifex/react';

function LanguageList () {
  const languages = useLanguages();
  return (
    <ul>
      {languages.map(({ code, name }) => (
        <li key={code}>
          <strong>{code}</strong>: {name}
        </li>
      ))}
    </ul>
  );
}

Optionally useLanguages can take as param a custom Native Instance:

import { useT } from '@transifex/react';
import { createNativeInstance } from '@transifex/native';

const customTX = createNativeInstance({
  token: 'token',
  secret: 'secret',
});

function Component() {
  const languages = useLanguages(customTX);
  // ...
}

useLocale hook

Returns a state variable with the currently selected locale.

import React from 'react';
import { useLocale } from '@transifex/react';

function DisplayLocale () {
  const locale = useLocale();
  return (
    <p>Currently selected locale is {locale}</p>
  );
}

Optionally useLocale can take as param a custom Native Instance:

import { useT } from '@transifex/react';
import { createNativeInstance } from '@transifex/native';

const customTX = createNativeInstance({
  token: 'token',
  secret: 'secret',
});

function Component() {
  const locale = useLocale(customTX);
  // ...
}

useTX hook

Returns a state variable with the Native instance.

import React from 'react';
import { useTX } from '@transifex/react';

function SetLocale () {
  const tx = useTX();
  return (
    <button onClick={() => tx.setCurrentLocale('el')}>
      Set to Greek
    </button>
  );
}

LanguagePicker component

Renders a <select> tag that displays supported languages and switches the application's selected language on change. Uses useLanguages and useLocale internally.

import React from 'react';
import { T, LanguagePicker } from '@transifex/react';

function App () {
  return (
    <div>
      <T _str="This is a translatable message" />
      <LanguagePicker />
    </div>
  );
}

Accepts properties:

• className: The CSS class that will be applied to the <select> tag

If you want something different than a <select>, it should be easy to write your own language picker using useLanguages:

import React from 'react';
import { tx } from '@transifex/native';
import { useLanguages, useLocale } from '@transifex/react';

function MyLanguagePicker () {
  const languages = useLanguages();
  const locale = useLocale();

  return (
    <>
      {languages.map(({ code, name }) => (
        <button key={code} onClick={() => tx.setCurrentLocale(code)}>
          {name} {locale === code ? '(selected)' : ''}
        </button>
      ))}
    </>
  );
}

useTranslations hook - aka Lazy Loading

Fetches translations tagged with a specific combination of tags when a component first renders. This way, you can pull translations from the CDS in batches and only when needed:

tx.init({ token: ..., filterTags: 'home' });

export default function App() {
  return (
    <>
      <T _str="This will be translated as soon as possible" _tags="home" />
      {someCondition() && <Inner />}
    </>
  );
}

function Inner() {
  useTranslations('inner');
  return <T
    _str="This will be translated when the inner component is rendered"
    _tags="inner" />;
}

The hook returns a boolean state variable called ready that you can use to handle a loading state:

function Inner() {
  const { ready } = useTranslations('inner');
  if (!ready) { return 'Loading...'; }
  return <T
    _str="This will be translated when the inner component is rendered"
    _tags="inner" />;
}

If you don't handle the loading state, the source string will be rendered first and then replaced with the translation when it becomes available.

You can also use the hook in parent components that don't need the tagged translations themselves. This will make the translations available sooner for child components that may potentially need them:

tx.init({ token: ..., filterTags: 'home' });

export default function App() {
  const { ready: innerReady } = useTranslations('inner');
  return (
    <>
      <T _str="This will be translated as soon as possible" _tags="home" />
      {someCondition() && <Inner ready={innerReady} />}
    </>
  );
}

function Inner({ ready }) {
  if (!ready) { return 'Loading...'; }
  return <T
    _str="This will be translated when the inner component is rendered"
    _tags="inner" />;
}

Optionally useTranslations can take as a second param a custom Native Instance:

import { useT } from '@transifex/react';
import { createNativeInstance } from '@transifex/native';

const customTX = createNativeInstance({
  token: 'token',
  secret: 'secret',
});

function Component() {
  const { ready } = useTranslations('inner', customTX);
  // ...
}

TXProvider provider

If you need to use more than one Transifex Native instances - like for example if you have a component library - you can use this provider to pass the desired instance to the children components.

import { tx, createNativeInstance } from '@transifex/native';
import { TXProvider, LanguagePicker, T } from '@transifex/react';

const myOtherTXInstance = createNativeInstance();
myOtherTXInstance.init({ token: 'othertoken' })

tx.init({
  token: 'token',
});

// Make tx aware of the other instances so they can be synced when changing
// language
tx.controllerOf(myOtherTXInstance);

export default function App() {
  return (
    <>
      <LanguagePicker />
      <TXProvider instance={myOtherTXInstance}>
        <T _str="Hello {username}" username="John" />
      </TXProvider>
      <T _str="Hello World" />
    </>
  );
}

License

Licensed under Apache License 2.0, see LICENSE file.