Best way to serialize unserialize objects in JavaScript

Question

I have many JavaScript objects in my application  something like   function Person age        this age   age      this isOld   function             return this age  gt  60             before serialize  ok var p1   new Person 77   alert  Is old      p1 isOld         after  got error Object   lt Object gt  has no method  isOld  var serialize   JSON stringify p1   var  p1   JSON parse serialize   alert  Is old       p1 isOld       See in JS Fiddle   My question is  is there a best practice pattern tip to recover my object in same type it was before serialization  instances of class Person  in this case    Requirements that I have    Optimize disk usage  I have a big tree of objects in memory  So  I don t want to store functions  Solution can use jQuery and another library to serialize unserialize

User · Answer

I tried to do this with Date with native JSON     function stringify  obj  any      return JSON stringify      obj      function  k  v          if  this k  instanceof Date            return    date    this k                 return v              function clone lt T gt   obj  T   T     return JSON parse      stringify obj           v    gt   Array isArray v   amp  amp  v 0        date     new Date v 1     v         What does this say  It says   There needs to be a unique identifier  better than  date  if you want it more secure    class Klass     static fromRepr  repr  string   Klass       return new Klass             static guid      Klass         repr       string       return               This is a serializable Klass  with  function serialize  obj  any      return JSON stringify      obj      function  k  v    return this k  instanceof Klass    Klass guid  this k    repr        v          function deserialize  repr  string      return JSON parse      repr          v    gt   Array isArray v   amp  amp  v 0      Klass guid    Klass fromRepr v 1     v         I tried to do it with Mongo-style Object     date    as well  but it failed in JSON parse  Supplying k doesn t matter anymore     BTW  if you don t care about libraries  you can use yaml dump   yaml load from js-yaml  Just make sure you do it the dangerous way

User · Answer

JSON has no functions as data types  You can only serialize strings  numbers  objects  arrays  and booleans  and null   You could create your own toJson method  only passing the data that really has to be serialized   Person prototype toJson   function         return JSON stringify  age  this age         Similar for deserializing    Person fromJson   function json        var data   JSON parse json      Parsing the json string      return new Person data age        The usage would be   var serialize   p1 toJson    var  p1   Person fromJson serialize   alert  Is old       p1 isOld         To reduce the amount of work  you could consider to store all the data that needs to be serialized in a special  data  property for each Person instance  For example   function Person age        this data             age  age            this isOld   function             return this data age  gt  60   true   false            then serializing and deserializing is merely calling JSON stringify this data  and setting the data of an instance would be instance data   JSON parse json    This would keep the toJson and fromJson methods simple but you d have to adjust your other functions     Side note   You should add the isOld method to the prototype of the function   Person prototype isOld   function        Otherwise  every instance has it s own instance of that function which also increases memory

User · Answer

I had a similar problem and since I couldn t find a sufficient solution  I also created a serialization library for javascript  https   github com wavesoft jbb  as a matter of fact it s a bit more  since it s mainly intended for bundling resources   It is close to Binary-JSON but it adds a couple of additional features  such as metadata for the objects being encoded and some extra optimizations like data de-duplication  cross-referencing to other bundles and structure-level compression   However there is a catch  In order to keep the bundle size small there are no type information in the bundle  Such information are provided in a separate  profile  that describes your objects for encoding and decoding  For optimization reasons this information is given in a form of script   But you can make your life easier using the gulp-jbb-profile  https   github com wavesoft gulp-jbb-profile  utility for generating the encodeing decoding scripts from simple YAML object specifications like this     The  Person  object has the  age  and  isOld    properties Person    properties      - age     - isOld   For example you can have a look on the jbb-profile-three profile  When you have your profile ready  you can use JBB like this   var JBBEncoder   require  jbb encode    var MyEncodeProfile   require  profile profile-encode        Create a new bundle var bundle   new JBBEncoder   path to bundle jbb         Add one or more profile s  in order for JBB    to understand your custom objects bundle addProfile MyEncodeProfile       Encode your object s  - They can be any valid    javascript object  or objects described in    the profiles you added previously   var p1   new Person 77   bundle encode  p1   person      var people             new Person 45           new Person 77                      bundle encode  people   people         Close the bundle when you are done bundle close      And you can read it back like this   var JBBDecoder   require  jbb decode    var MyDecodeProfile   require  profile profile-decode        Instantiate a new binary decoder var binaryLoader   new JBBDecoder   path to bundle         Add your decoding profile binaryLoader addProfile  MyDecodeProfile        Add one or more bundles to load binaryLoader add   bundle jbb         Load and callback when ready binaryLoader load function  error  database             Your objects are in the database        and ready to use      var people   database  people

User · Answer

The browser s native JSON API may not give you back your idOld function after you call JSON stringify  however  if can stringify your JSON yourself  maybe use Crockford s json2 js instead of browser s API   then if you have a string of JSON e g   var person json        age      20    isOld     false  isOld  function     return this age  gt  60          then you can call   eval       person             and you will get back your function in the json object

User · Answer

I ve added yet another JavaScript serializer repo to GitHub   Rather than take the approach of serializing and deserializing JavaScript objects to an internal format the approach here is to serialize JavaScript objects out to native JavaScript  This has the advantage that the format is totally agnostic from the serializer  and the object can be recreated simply by calling eval     https   github com iconico JavaScript-Serializer

User · Answer

I wrote serialijse because I faced the same problem as you   you can find it at https   github com erossignon serialijse  It can be used in nodejs or in a browser and can serve to serialize and deserialize a complex set of objects from one context  nodejs  to the other  browser  or vice-versa   var s   require  serialijse      var assert   require  assert         testing serialization of a simple javascript object with date function testing javascript serialization object with date          var o             date  new Date            name   foo             console log o name  o date toISOString             JSON will fail as JSON doesn t preserve dates     try           var jstr   JSON stringify o           var jo   JSON parse jstr           console log jo name  jo date toISOString           catch  err            console log   JSON has failed to preserve Date during stringify parse             console log    and has generated the following error message   err message             console log             var str   s serialize o       var so   s deserialize str       console log   However Serialijse knows how to preserve date during serialization deserialization          console log so name  so date toISOString         console log        testing javascript serialization object with date         serializing a instance of a class function testing javascript serialization instance of a class          function Person             this firstName    Joe           this lastName    Doe           this age   42             Person prototype fullName   function              return this firstName         this lastName                  testing serialization using  JSON stringify JSON parse     var o   new Person        console log o fullName      age    o age        try           var jstr   JSON stringify o           var jo   JSON parse jstr           console log jo fullName      age    jo age          catch  err            console log   JSON has failed to preserve the object class             console log    and has generated the following error message   err message             console log              now testing serialization using serialijse  serialize deserialize     s declarePersistable Person       var str   s serialize o       var so   s deserialize str        console log   However Serialijse knows how to preserve object classes serialization deserialization          console log so fullName      age    so age     testing javascript serialization instance of a class         serializing an object with cyclic dependencies function testing javascript serialization objects with cyclic dependencies          var Mary     name   Mary   friends            var Bob     name   Bob   friends             Mary friends push Bob       Bob friends push Mary        var group     Mary  Bob       console log group           testing serialization using  JSON stringify JSON parse     try           var jstr   JSON stringify group           var jo   JSON parse jstr           console log jo          catch  err            console log   JSON has failed to manage object with cyclic deps            console log    and has generated the following error message   err message                 now testing serialization using serialijse  serialize deserialize     var str   s serialize group       var so   s deserialize str       console log   However Serialijse knows to manage object with cyclic deps          console log so       assert so 0  friends 0     so 1       Mary s friend is Bob   testing javascript serialization objects with cyclic dependencies

User · Answer

I am the author of https   github com joonhocho seri   Seri is JSON   custom  nested  class support   You simply need to provide toJSON and fromJSON to serialize and deserialize any class instances   Here s an example with nested class objects   import seri from  seri    class Item     static fromJSON    name    gt  new Item name     constructor name        this name   name         toJSON         return this name         class Bag     static fromJSON    itemsJson    gt  new Bag seri parse itemsJson      constructor items        this items   items         toJSON         return seri stringify this items             register classes seri addClass Item   seri addClass Bag     const bag   new Bag     new Item  apple      new Item  orange          const bagClone   seri parse seri stringify bag         validate bagClone instanceof Bag   bagClone items 0  instanceof Item  bagClone items 0  name      apple    bagClone items 1  instanceof Item  bagClone items 1  name      orange     Hope it helps address your problem

User · Answer

I had the exact same problem  and written a small tool to do the mixing of data and model  See https   github com khayll jsmix  This is how you would do it     model object  or whatever you d like the implementation to be  var Person   function      Person prototype isOld   function         return this age  gt  RETIREMENT AGE       then you could say  var result   JSMix jsonData  withObject Person prototype   persons   build       and use console log result persons 3  isOld       It can handle complex objects  like nested collections recursively as well   As for serializing JS functions  I wouldn t do such thing because of security reasons

[javascript] Best way to serialize/unserialize objects in JavaScript?

Examples related to javascript

Examples related to serialization