Can we cast a generic object to a custom object type in javascript

Question

For example  I already have this object somewhere in the code  it is a generic object   var person1  lastName  Freeman  firstName  Gordon      I have the constructor for a Person object   function Person     this getFullName function      return this lastName         this firstName         Is there a simple syntax that allows us to convert person1 to an object of type Person

User · Answer

This worked for me  It s simple for simple objects    x000D   x000D  class Person   x000D    constructor firstName  lastName    x000D      this firstName   firstName  x000D      this lastName   lastName  x000D      x000D    getFullName     x000D      return this lastName         this firstName  x000D      x000D   x000D    static class obj    x000D      return new Person obj firstName  obj lastName   x000D      x000D    x000D   x000D  var person1     x000D    lastName   Freeman   x000D    firstName   Gordon  x000D     x000D   x000D  var gordon   Person class person1   x000D  console log gordon getFullName     x000D   x000D   x000D    I was also searching for a simple solution  and this is what I came up with  based on all other answers and my research  Basically  class Person has another constructor  called  class  which works with a generic object of the same  format  as Person  I hope this might help somebody as well

User · Answer

This borrows from a few other answers here but I thought it might help someone  If you define the following function on your custom object  then you have a factory function that you can pass a generic object into and it will return for you an instance of the class   CustomObject create   function  obj        var field   new CustomObject        for  var prop in obj            if  field hasOwnProperty prop                 field prop    obj prop                        return field      Use like this  var typedObj   CustomObject create genericObj

User · Answer

This is not exactly an answer  rather sharing my findings  and hopefully getting some critical argument for against it  as specifically I am not aware how efficient it is   I recently had a need to do this for my project  I did this using Object assign  more precisely it is done something like this Object assign new Person       anObjectLikePerson    Here is link to my JSFiddle  and also the main part of the code   function Person firstName  lastName      this firstName   firstName    this lastName   lastName     this getFullName   function         return this lastName         this firstName         var persons        lastName   Freeman     firstName   Gordon         lastName   Smith     firstName   John       var stronglyTypedPersons       for  var i   0  i  lt  persons length  i        stronglyTypedPersons push Object assign new Person          persons i

User · Answer

The answer of  PeterOlson may be worked back in the day but it looks like Object create is changed    I would go for the copy-constructor way like  user166390 said in the comments    The reason I necromanced this post is because I needed such implementation    Nowadays we can use Object assign  credits to  SayanPal solution   amp  ES6 syntax   class Person     constructor obj        obj  amp  amp  Object assign this  obj          getFullName         return    this lastName    this firstName            Usage   const newPerson   new Person person1  newPerson getFullName      - gt  Freeman Gordon   ES5 answer below  function Person obj        for var prop in obj              for safety you can use the hasOwnProperty function         this prop    obj prop             Usage   var newPerson   new Person person1   console log newPerson getFullName        - gt  Freeman Gordon   Using a shorter version  1 5 liner   function Person        if arguments 0   for var prop in arguments 0   this prop    arguments 0  prop       jsfiddle

User · Answer

This is just a wrap up of Sayan Pal answer in a shorter form  ES5 style    var Foo   function        this bar   undefined      this buzz   undefined     var foo   Object assign new Foo         bar   whatever       buzz   something else        I like it because it is the closest to the very neat object initialisation in  Net   var foo   new Foo         bar   whatever

User · Answer

No    But if you re looking to treat your person1 object as if it were a Person  you can call methods on Person s prototype on person1 with call   Person prototype getFullNamePublic   function        return this lastName         this firstName    Person prototype getFullNamePublic call person1     Though this obviously won t work for privileged methods created inside of the Person constructor   like your getFullName method

[javascript] Can we cast a generic object to a custom object type in javascript?

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