Javascript JSON.stringify doesn't handle prototype correctly?

Question

I\'ve been initializing my reusable classes like this (constructor is usually a copy-constructor):

function Foo() {}
Foo.prototype.a = \"1\";
Foo.prototype.b         


        

Answer 1

Properties on an object's prototype (that is, the prototype of its constructor) are readable via a reference to an the object:

function Constructor() { }
Constructor.prototype.a = "hello world";

var x = new Constructor();
alert(x.a); // "hello world"

However, those properties really are "stuck" on the prototype object:

alert(x.hasOwnProperty("a")); // false

The JSON serializer only pays attention to properties that directly appear on objects being processed. That's kind-of painful, but it makes a little sense if you think about the reverse process: you certainly don't want JSON.parse() to put properties back onto a prototype (which would be pretty tricky anyway).

Answer 2

your answer lies Why is JSON.stringify not serializing prototype values?

JSON.stringify only does "own" properties.

In your first example: prototype members are being set, and then calling Stringify on the object itself, which does not have its own properties.

In your second: this.a will climb the chain until it finds the property

In the third: You are setting properties directly on the object and not its prototype