how to declare objects in js code example

Example 1: objects in javascript

let object = {
  'key1': 'value1',
  'key2': 'value2',
  'keyn': 'valuen',
};
console.log(object);

Example 2: 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.");