How to implement localization in reactjs?

We use react-i18next. And then use i18nexus to auto-translate and manage translations.

Yahoo has created a package for implementing localization in React that might be what you are looking for: https://github.com/yahoo/react-intl. It takes care of "dates, numbers, and strings, including pluralization and handling translations".

Update 2021: Here's the package now days:

• https://github.com/formatjs/formatjs
• https://www.npmjs.com/package/react-intl

npm install react-localization

import ReactDOM from 'react-dom';
import React, { Component } from 'react';
import LocalizedStrings from 'react-localization';

let strings = new LocalizedStrings({
  en:{
    how:"How do you want your egg today?",
    boiledEgg:"Boiled egg",
    softBoiledEgg:"Soft-boiled egg",
    choice:"How to choose the egg"
  },
  it: {
    how:"Come vuoi il tuo uovo oggi?",
    boiledEgg:"Uovo sodo",
    softBoiledEgg:"Uovo alla coque",
    choice:"Come scegliere l'uovo"
  }
 });

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      language: 'en'
    }
    
    this.handleLanguageChange = this.handleLanguageChange.bind(this);
  }

  handleLanguageChange(e) {
    e.preventDefault();
    let lang = e.target.value;
    this.setState(prevState => ({
      language: lang
    }))
  }

  render() {
    strings.setLanguage(this.state.language);
    return (
      <div>
        Change Language: <select onChange={this.handleLanguageChange}>
          <option value="en">En- English</option>
          <option value="it">It- Italian</option>
        </select>
        <br /><br />
        {strings.how}
      </div>
    )
  }
}

ReactDOM.render(<App />, document.getElementById('root'));

u can put your language specific data in a JSON file or or .js file. call that file in your current file and pass that object to new LocalizedStrings().

Example: data.js

const data = {
  en:{
    how:"How do you want your egg today?",
    boiledEgg:"Boiled egg",
    softBoiledEgg:"Soft-boiled egg",
    choice:"How to choose the egg"
  },
  it: {
    how:"Come vuoi il tuo uovo oggi?",
    boiledEgg:"Uovo sodo",
    softBoiledEgg:"Uovo alla coque",
    choice:"Come scegliere l'uovo"
  }
}
export {data};

in your current file import it as import { data } from './data.js'; and then you can initialise as let strings = new LocalizedStrings({data});

You can read the detailed article here - react-localization with hooks

Check the working demo Here