json stringify can deal with circular reference

stringify.js

// http://stackoverflow.com/questions/11616630/json-stringify-avoid-typeerror-converting-circular-structure-to-json/11616993#11616993
var o = {};
o.o = o;

var cache = [];
JSON.stringify(o, function(key, value) {
    if (typeof value === 'object' && value !== null) {
        if (cache.indexOf(value) !== -1) {
            // Circular reference found, discard key
            return;
        }
        // Store value in our collection
        cache.push(value);
    }
    return value;
});
cache = null; // Enable garbage collection

This can now be implemented with latest javascript API too.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Cyclic_object_value

It is the same right?

why not wrapping it in a function like I did in this fork:
https://gist.github.com/boussou/ca738c68b1850115e314979a8ae69b58

this is plain wrong. The multiple ocurrence of the same reference in the same structure does not necessarily implies circularity. You'd have to do something recursive.

var x = {}
var a = {
  b: x,
  c: x
}

yeah, it has this bug with having the same object in a different branches
you can use my version which addresses this
https://gist.github.com/saitonakamura/d51aa672c929e35cc81fa5a0e31f12a9