arson  

$3

_Not to be confused with the criminal act of deliberately setting fire to property!_

JSON is great until you need to encode an object with circular references:
``js
var obj = {};
obj.self = obj;
JSON.stringify(obj); // throws
`

Throwing an exception is lame, but even worse is muddling along as if everything is ok:
`js
var a = {};
var b = { foo: 42 };
a.x = a.y = b;
var c = JSON.parse(JSON.stringify(a));
assert.strictEqual(c.x, c.y); // fails
`

We need an object notation that supports circular and repeated references.

That's where ARSON comes in:
`js
var a = {};
var b = { foo: 42 };
a.x = a.y = b;
var c = ARSON.parse(ARSON.stringify(a));
assert.strictEqual(c.x, c.y); // no problem!
`

ARSON is compact, often even more compact than JSON, because repeated objects are defined only once:
`js
var a = {};
var b = { foo: 42 };
a.x = a.y = b;
ARSON.stringify(a); // [{"x":1,"y":1},{"foo":2},42] vs.
// {"x":{"foo":42},"y":{"foo":42}}
`

But that's not all! ARSON can also encode undefined, thanks to the fact that [][-1] is always undefined:
`js
> ARSON.encode({foo:undefined})
'[{"foo":-1}]'
> ARSON.decode(_)
{ foo: undefined }
`

It can also encode array holes:
`js
> ARSON.encode(Array(3).concat([4, 5]))
'[[-2,-2,-2,1,2],4,5]'
> ARSON.decode(_)
[ , , , 4, 5 ]
`

Buffers:
`js
> ARSON.encode(new Buffer("asdf"))
'[["Buffer","YXNkZg==","base64"]]'
> ARSON.decode(_)

`

Dates:
`js
> ARSON.encode(new Date)
'[["Date","2016-02-02T00:25:36.886Z"]]'
> ARSON.decode(_)
Mon Feb 01 2016 19:25:36 GMT-0500 (EST)
`

RegExps:
`js
> ARSON.encode(/asdf/img)
'[["RegExp","asdf","img"]]'
> ARSON.decode(_)
/asdf/gim
`

Sets:
`js
> s = new Set
Set {}
> s.add(s)
Set { Set { Set { [Object] } } }
> ARSON.encode(s)
'[["Set",0]]'
> ARSON.decode(_)
Set { Set { Set { [Object] } } }
> _.has(_)
true
`

and Maps:
`js
> m = new Map
Map {}
> m.set(1234, m)
Map { 1234 => Map { 1234 => Map { 1234 => [Object] } } }
> m.set(m, 5678)
Map {
1234 => Map {
1234 => Map {
1234 => [Object],
[Object] => 5678
},
Map {
1234 => [Object],
[Object] => 5678
} => 5678
},
Map {
1234 => Map {
1234 => [Object],
[Object] => 5678
},
Map {
1234 => [Object],
[Object] => 5678
} => 5678
} => 5678
}
> ARSON.encode(m)
'[["Map",1,2],[3,0],[0,4],1234,5678]'
> ARSON.decode(_)
Map {
1234 => Map {
1234 => Map {
1234 => [Object],
[Object] => 5678
},
Map {
1234 => [Object],
[Object] => 5678
} => 5678
},
Map {
1234 => Map {
1234 => [Object],
[Object] => 5678
},
Map {
1234 => [Object],
[Object] => 5678
} => 5678
} => 5678
}
> _.get(_.get(1234)) === 5678
true
``