create javascript object with new keyword what makes difference code example

Example 1: how to create object js

function person(fname, lname, age, eyecolor){
  this.firstname = fname;
  this.lastname = lname;
  this.age = age;
  this.eyecolor = eyecolor;
}

myFather = new person("John", "Doe", 50, "blue");
document.write(myFather.firstname + " is " + myFather.age + " years old.");

Example 2: js create new object

let bike = {   name: 'SuperSport',    maker:'Ducati',    start: function() {       console.log('Starting the engine...');   }};bike.start();   //Output: Starting the engine.../* Adding method stop() later to the object */bike.stop = function() {    console.log('Applying Brake...');  }bike.stop();    //Output: Applying Brake...