json - Javascript objects parsed vs created -

what practical difference between p , p2 objects here:

var person = function(name) { this.name=name; } var p = new person("john");  var p2 = json.parse('{"name":"john"}'); 

what cases when better create new person() , copy values parsed json, rather use parsed json object use instance of person?

ps. let's got json string websocket , have parse anyway.

the main difference p object, instance of person while p2 "plain" object, instance of object.

when difference important?

1) accessing prototype properties:

var person = function(name) { this.name=name; } person.prototype.getname = function () {     return this.name; };  p.getname() //works fine p2.getname() //error since getname not defined 

or:

console.log(p.constructor) //person console.log(p2.constructor) //object 

2) using instanceof operator:

p instanceof person //true p2 instanceof person //false 

3) has inheritance

all 3 points can traced prototype chain, looks both ways:

p --> person --> object  p2 --> object 

now, since have constructor function suggest use it, because can quite messy if mix person objects plain objects. if want object, has name property, fine in both ways, gets little bit more complex, can run severe problems.