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?

Answer 1

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) & ES6 syntax:

class Person {   constructor(obj) {     obj && Object.assign(this, obj);   }    getFullName() {     return `${this.lastName} ${this.firstName}`;   } } 

Usage:

const newPerson = new Person(person1) newPerson.getFullName() // -> 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()); // -> 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