Define getter / setter in object function

Question

I'm learning JavaScript, and was wondering if it was possible to define getters and setters in object functions. The main difference is the way of calling it, if defined as getFullName = function() , I should call the method as myObj.getFullName() , however, as for arrays, a getter allows for it to be called as a simple property myObj.fullName (without parenthesis).

As I saw in MDN reference ( http://mzl.la/1CIUuIw ), it is easily done in Object Literals:

var obj = {
    get var(){
        return "something";
    }
}

However, I can't do it on object functions like so:

function obj(name, lname){
    this.name = name;
    this.lastName = lname;

    get fullName(){
         return this.name + " " + this.lastName;
    }
}

Getting a "Unexpected identifier" error...

Answer 1

As get XX(){} is used for var obj = {}; But here you use a constructor to create new object. So you should use MDN - Object.defineProperty() .

And if you want the fullName apply on all object create from obj , apply it on its prototype.

 function obj(name, lname){ this.name = name; this.lastName = lname; } Object.defineProperty(obj.prototype, 'fullName', { get : function() { return this.name + " " + this.lastName; } }); var aObj = new obj("first", 'lastN'); console.log(aObj.fullName); 

UPDATE: If you want a more straight way, and not scared to try new things, then ES2015 's class notation can do it more easily:

// ES2015 - class
class obj {
  constructor(name, lname) {
    this.name = name;
    this.lname = lname;
  }

  // Define getter method for fullName
  get fullName() {
    return this.name + " " + this.lastName;
  }
}

var aObj = new obj('Billy', 'Hallow');
console.log(aObj.fullName);

Currently most browsers don't support that, if you want to use this in your site, you need to use js compilers like Babel to transpile it from ES2015 to ES5.

Babel also provide a playground for those who has interest in ES2015, you can copy above codes to the playground to see how it works.

Answer 2

Just make a variable and assign the function to it.

function obj(name, lname){
    this.name = name;
    this.lastName = lname;

    this.fullName = function(){
        return this.name + " " + this.lastName;
    };
}

Try to read something about Javascript closure if you want to know more about it.

Furthermore, this link, Javascript methods , is explaining EXACTLY what you need, which is adding a method to an object. And a getter is traditionally just a method.

Answer 3

function obj(name, lname){
    this.name = name;
    this.lastName = lname;
}
obj.prototype.getfullName = function(){
    return this.name + " " + this.lastName;
}

use this as

a = new obj("My","Name");
a.getfullName() //"My Name"

Answer 4

Javascript uses prototype inheritance and its functions start with function keyword. By convention, object's first character is capitalised.

function Obj(name, lname){
    this.name = name;
    this.lastName = lname;
}

Obj.prototype.get = function() {
     return this.name + " " + this.lastName;
}

var person = new Obj('luke', 'lim');
console.log(person.get()); // 'luke lim'