How to make multilingual node.js app?!

Hello!

You are looking how to easy make multilingual website with seo urls? You are in right place! I will tell you about "smws" module.

So we are going to test this module, full test code can be found on Github.
Check npmjs.com for documentation.

First off all, setup app.js. "smws" module work with Express, body-parser, cookie-parser and view engine (tested with Eta and ejs).

Module install:

npm i express body-parser cookie-parser eta smws

app.js example:

const express = require('express'),
      cookieParser = require('cookie-parser'),
      bodyParser = require("body-parser"),
      smws = require("smws"),
      app = express();

app.set('view engine', 'Eta');

app.use(bodyParser.urlencoded({extended: true}));
app.use(express.static(__dirname + '/public'));
app.use(cookieParser());

app.listen(process.env.PORT || 3000, () => {
   console.log('Server running on port 3000');
});

Next step, we need to configure "smws":

smws.config({
    languages: ['en','ru'],
    defaultLang: 'en'
});

So, I will use two languages and default is 'en'. I don't need to add other options in config because they can stay with default values.

Language switcher

To change language from front-end setup view engine templates. We need form to send chosen language to the server:

<!-- action will be "/<%= smws.lang %>/language" if you use ejs -->
<!-- I'm using eta view engine -->
<form action="/<%= it.smws.lang %>/language" method="post">
    <button class="en-button" type="submit" name="lang" value="en">EN</button>
    <button class="ru-button" type="submit" name="lang" value="ru">RU</button>
</form>

To receive this language changes, add to your app.js:

app.post('/:lang/language', (req,res)=>{
    smws.switcher(req,res);
});

smws.switcher(req,res); controles language changes.

GET requests with smws

Next we add our paths to app.js:

app.get('/', function (req, res) {
    smws.run(req, res, {
        page: 'index'
    });
});

app.get('/:lang', function (req, res) {
    smws.run(req, res, {
        page: 'index'
    });
});

app.get(smws.split('/:lang/:category'), function (req, res) {
    smws.run(req,res,{
        page: 'category',
        useParams: ['lang', 'category']
    });
});

smws.split('path') use for your paths where you need to translate and control more than only language parameter.
smws.run(req,req,{options}); use to response your template and control parameters. page: option is mandatory.

I'm using two paths for homepage to cover main url like domain.com and with language param like domain.com/en.

When user first time visit your main page, it will be rendered in default language which chosen in smws.config({....

If someone visit your website using some url. For example click somewhere domain.com/ru/kategoriya, page will be rendered in ru language, so chosen from params.

Language files

In the end we need language files. By default "smws" use .json files from "languages" folder in root directory. But you can change it in:

smws.config({
...
langDir: 'your/dir/name'
...
});

Language file names must be same with your website languages. In this tutorial en.json and ru.json.
Example:

//en.json
{
    "smws": {

            "category": "category",
            "lang": "en"

    },
    "hello": "This is main page in 'EN'"
}

//ru.json
{
    "smws": {

            "category": "kategoriya",
            "lang": "ru"

    },
    "hello": "Главная страница на 'RU'"
}

So in the end we get:

• website with changeable languages,
• can set SEO friendly urls,
• only one app.get(... for all languages,
• no page duplicates like domain.com/ru/kategoriya and domain.com/ru/category. Last one will send 404 status because param :category does not match :lang param "ru".

Thank you for attention! Hope this will be helpful for someone!