Singleton pattern in JS

single.js

let Singleton  = (function(name, yearOfBirth, job, relationship){
  let instance;

  function init(){
    return {
      name: name,
      age: new Date().getFullYear() - yearOfBirth,
      job: job,
      relationship: relationship
    }
  }

  if(!instance){
    instance  = init();
  }
  return instance;

})("Fares", 1993, "Software engineer", "Single");

console.log(Singleton);