Cereal

Serialisation Library for JavaScript that respects object aliases, copes with cycles in the object graph, understands undefined, and can cope with arrays that have arbitrary properties.

Can be used either client-side or in NodeJS.

What does it solve?

Aliases

var x = {};
var y = {a: x, b: x};

If you take the above and then do JSON.parse(JSON.stringify(y)) then you will lose the alias to x: what you'll get back will be {a: {}, b: {}}.

If you instead do Cereal.parse(Cereal.stringify(y)) then you'll get back the correct object shape, with both a and b pointing to the same object.

Loops

JSON can't cope with cyclical data structures. Cereal can.

var x = {};
x.x = x;

JSON will blow up if you try to stringify(x). Cereal will work correctly.

Undefined

JSON can't represent undefined. Cereal can.

 var x = {a: undefined};

JSON.parse(JSON.stringify(x)) will yield {}. Cereal will get it right.

Array fields

JSON thinks arrays can't have arbitrary properties, and will drop them. Cereal won't.

  var x = [5];
  x.foo = true;

JSON.parse(JSON.stringify(x)) will yield [5]. Cereal will get it right.

Anything else?

JSON invokes toJSON on an object before encoding it. Analogously to this, Cereal invokes a cerealise function if it exists and encodes what is returned from that.

Note that Cereal first rewrites the object structure to something without loops or aliases (but from which the loops and aliases can be reconstructed) and then it just uses normal JSON encoding on the result, and vice-versa.

As a result, Cereal will ignore everything that JSON would ignore too. Thus as normal, you lose functions, prototypes etc etc.