Variable replacement with i18next and handlebars

Question

I've finally gotten my PhoneGap / Backbone / Handlebars to localize using i18next.js -- kind of.

I'm currently wondering how to get html with embedded handlebars expressions to both localize and compile with Handlebars. As an example, I want something like this:

Welcome, {{this.name}}. We've been expecting you.

to turn into:

Welcome, Bob. We've been expecting you.

That's easy enough without localization. But run through the i18next template described in the docs (here: http://i18next.com/pages/doc_templates.html)...

// handlebars helper from i18next
Handlebars.registerHelper('t', function(i18n_key) {
  var result = i18n.t(i18n_key);
  return new Handlebars.SafeString(result);
});

//Handlebars string:
{{t 'view.WelcomeMessage'}}

// translation.json file
{ "view":
    {
        "WelcomeMessage": "Welcome, {{this.name}}. We've been expecting you."
    }
}

Unfortunately, this turns into the following when localized:

Welcome, {{this.name}}. We've been expecting you.

How do I get the string to localize and have embedded expression compile?

Answer 1

It looks like the the answer for this is in the variable replacement helper tr:

// handlebars helper from i18next
Handlebars.registerHelper('tr', function(context, options) { 
  var opts = i18n.functions.extend(options.hash, context);
  if (options.fn) opts.defaultValue = options.fn(context);
  var result = i18n.t(opts.key, opts);
  return new Handlebars.SafeString(result);
});

// random "This" object passed in:
var person = {name:"Bob", age:42, eyeColor:"blue"};

//Handlebars string:
{{tr this key='view.WelcomeMessage'}}

// translation.json file
{ "view":
  {
    "WelcomeMessage": "Welcome, __name__. We've been expecting you."
  }
}

// Output
Welcome, Bob. We've been expecting you.

Note that the tr example given on http://i18next.com/pages/doc_templates.html does have an extra parameter at the end. This is only necessary if you want to replace one of the this attributes with something else.

Answer 2

For i18next v3.2.0, which has interpolation:

package.json | dependencies/dev dependencies

"i18next": "^3.1.0",
"babel-core": "^6.7.2",
"babel-loader": "^6.2.4",
"handlebars": "^4.0.2",
"handlebars-loader": "^1.1.4",
"webpack": "^1.12.2",

layoutView.js | example of the model data being passed to the template:

  render(){
    let person = {name: 'joe', age: 21};
        person = new Backbone.Model(person);
    this.$el.html(template(person.toJSON()));
  }

layoutView.hbs | handlebars template

<div>{{{ i18n 'person' name=this.name age=this.age}}}</div>
<!-- after interpolation will read -->
<!-- <div>joe is 21 lang: en </div> -->

i18n.js | using es2015 so file name becomes the helperName used in layoutView.hbs (above)

// handlebars helper from i18next
import i18next from 'i18next';
import Handlebars from 'handlebars';

export default function(key, options) {
 let result = i18next.t(key, options.hash);
 return new Handlebars.SafeString(result);
};

translation.json | sample for interpolation

{
  "person": "{{name}} is {{age}} lang: en",
  "good-bye": "good-bye: en",
  "other": "other: en"
}

This thread on github really helped