node package manager
Stop writing boring code. Discover, share, and reuse within your team. Create a free org »


jsoni (JSON improved)

Serialize and deserialize Javascript objects into JSON

It will stringify and parse these values (which JSON.stringify and JSON.parse will not):

  • NaN
  • Infinity
  • new Date()
  • new Buffer()
  • new RegExp()
  • all builtin error constructs (Error, SyntaxError, TypeError, ReferenceError, RangeError, EvalError, URIError)

If any core javascript objects are missing, please submit an issue or pull request

var obj = {
    a: NaN,
    b: Infinity,
    c: /[abc]+def/gi
var objStr = jsoni.stringify(obj);
    "a": "NaN",
    "b": "Infinity",
    "c": {
        "constructName": "RegExp",
        "data": {
            "source": "[abc]+def",
            "flags": "gi"
var objB = jsoni.parse(objStr);
// objB.c is a regular expression clone of obj.c 
// '/[abc]+def/gi' 
// true 


npm install jsoni




jsoni.stringify(value, [ replacer ], [ space ])

same as JSON.stringify

jsoni.parse(value, [ reviver ])

same as JSON.parse

jsoni.register(name, constructor, [ options ])

registers a constructor to serialize and deserialize


  • serialize - Function to serialize an object. May return any value that can be stringified.
  • deserialize - Function to reconstruct an object. Should return a constructed object
var jsoni = require('jsoni');
function Person(name, age) { = name;
    this.age = age;
Person.prototype.greet = function () {
    return 'hello, my name is ' + + ' and I am ' + this.age + ' years old';
jsoni.register('Person', Person, {
    serialize: function (person) {
        return {
            age: person.age
    deserialize: function (obj) {
        return new Person(, obj.age);
var me = new Person('Jayce', 22);
var str = jsoni.stringify(me);
// '{"constructName":"Person","data":{"name":"Jayce","age":22}}' 
var newMe = jsoni.parse(str);
// 'hello, my name is Jayce and I am 22 years old' 


If a constructor's prototype has a toJSON method, then serialize does not need to be specified. serialize will take precedence over toJSON if it is specified. If neither are specified, then the default behavior of JSON.stringify is used.


If a constructor has a fromJSON method (ex: Person.fromJSON, not Person.prototype.fromJSON), then deserialize does not need to be specified. deserialize will take precedence over fromJSON if it is specified. If neither are specified, then the json data will be passed directly into the constructor (new Constructor(data)).


unregister a constructor from jsoni


  • undefined connot be stringified or parsed
  • Will not work between REPL or browser frames. It checks the equality of an objects constructor to registered constructors. REPL and frame constructors are not equal to the same constructor in another frame.