What is the difference between these three declaration of object in java script ?

Question

https://code.sololearn.com/WvPEs6P32prt/?ref=app
// using object notation
var person1={ name:"coder", job:"coding", work:function(){ console.log("code code code..")}};
//using constructor.
function person2()
{
this.name="coder";
this.job="coding"
this.work=function(){
console.log("code code code..")
}
}
var ob=new person2();
//using class
class person3
{
constructor(){
this.name="coder";
this.job="coding";
}
work()
{
console.log("code code code..");
}
}

Answer 1

To be precise, the first object person1 is an object entity which stores value in key-value format. And those values can be changed during runtime.
In the second example, person2 is a function, and using new keyword converts a function call to a constructor call.
In the third using class concept, which had been introduced in ES6, we can create a class and it's method and constructors. And like other languages, we can create an object of those class using the new keyword and calling the constructor.
Execution: (work method)
For example 1:
person1.work();
For example 2:
ob.work();
For Example 3:
var obj = new Person3();
obj.work();
Speaking of this keyword, Every function, while executing has a reference to its current execution context called  'this'.
And in class as well 'this' represents the reference to its instance properties.

Answer 2

Sami Khan thanks