How to json strinfigy a function instance in javascript?

Question

If I have this code

var node = function(n) {

    var name = n;
    var children = [];
    var finished = false;
    var failed = false;

    this.getName = function() {
        return name
    };
    this.downloadData = function(obj) {

    };

    this.getChildren = function() {
        return children;
    };
    this.setChildren = function(c) {
        Array.prototype.push.apply(children, c);
    };
    this.isFinished = function() {
        return finished;
    };
    this.setFinished = function() {
        finished = true;
    }
    this.isFailed = function() {
        return failed;
    }
    this.setFailed = function() {
        failed = true;
    }
};

How can I convert this into an object like:

var a = new node("a");
var j = JSON.stringify(a);

result

{"name":"a","children":[],"finished":false,"failed":false}

thanks

I think the title is poorly chosen. It sounds like you want to convert a function to a string, where you seem to want to convert an object created via new ..... to convert to JSON. FYI, it doesn't matter where the object came from. — Felix Kling
– Felix Kling, Commented Mar 24, 2015 at 20:48

Jite · Accepted Answer · 2015-03-24 20:50:01Z

4

This could be done by implementing the toJSON function.

If an object being stringified has a property named toJSON whose value is a function, then the toJSON() method customizes JSON stringification behavior: instead of the object being serialized, the value returned by the toJSON() method when called will be serialized. - Mozilla

eg:

var node = function(n) {

  var name = n;
  var children = [];
  var finished = false;
  var failed = false;

  this.toJson = function toJson() {
    return {"name":name ... };
  } 

 }

answered Mar 24, 2015 at 20:50

Jite

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3 Comments

omega Over a year ago

but what do u call on "children"?

Jite Over a year ago

That depends on what the children are, your question just indicates that its an array.

omega Over a year ago

children can contain more nodes.

KJ Price · Accepted Answer · 2015-03-24 20:50:46Z

2

You need object properties instead of variables.

So, instead of declaring var name = n;, you would declare this.name = n;. Which would make it look something like

var node = function(n) {
    this.name = n;
    this.children = [];
    this.finished = false;
    this.failed = false;
    ///other functions here
}

edited Mar 24, 2015 at 20:50

answered Mar 24, 2015 at 20:45

KJ Price

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2 Comments

Jite Over a year ago

This would change the access modifiers of the variables from being private/local to public. Might not be what OP intended them to be, seing he/she has created get/set for them.

KJ Price Over a year ago

Ah, that's an interesting point. In which case, your solution is definitely the way to go. If the the end result was a flat JSON object, I'm wondering why the getters/setters would be necessary. You could not use them when the JSON string was parsed later.

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