Пример

JavaScript

'use strict';

function GreetingsCreator() {

  let options = {
    name: 'Vasya',
    string: 'Привет'
  };

  this.lang = function(lang) {
    switch (lang) {
      case 'ru':
        options.string = 'Привет';
        break;
      case 'de':
        options.string = 'Hallo';
        break;
      case 'en':
      default:
        options.string = 'Hello';
        break;
    }
    return this;
  };

  this.userName = function(userName) {
    options.name = userName;
    return this;
  };

  this.makeGreet = function() {
    return `${options.string}, ${options.name}!`;
  };
  
}

console.log(new GreetingsCreator().lang('ru').userName('Петя').makeGreet());