Cannot access object method in Javascript

Question

I declare class user, and then added an object of the class

function user(uid, pwd){
    this.uid = uid
    this.pwd = pwd
    function displayAll(){
        document.write(uid)
        document.write(pwd)
    }
}

var Aaron = new user("Aaron", "123")

document.write(Aaron.uid)

I want to roll through the properties printing them out one by one, I tried this

Aaron.displayAll()

which evaluates to nothing, am I missing something? Any help would be amazing :)

The function is declared withing the user function, but never binded to it, hence it's not exposed and can't be accessed, resulting in a function available only inside the user function. — briosheje
– briosheje, Commented Apr 15, 2019 at 6:54

mbojko · Accepted Answer · 2019-04-15 06:59:49Z

7

This is what prototype chain is for.

function User(uid, pwd) {
  this.uid = uid
  this.pwd = pwd
}

User.prototype.displayAll = function() {
  document.write(this.uid)
  document.write(this.pwd)
}


var aaron = new User("Aaron", "123");


aaron.displayAll();

answered Apr 15, 2019 at 6:59

mbojko

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Comments

Razana N. · Accepted Answer · 2019-04-15 07:13:14Z

1

Another way is to use Class syntax.

class User {
  constructor(uid, pwd) {
    this.uid = uid;
    this.pwd = pwd;
  }

displayAll(){
    document.write(this.uid);
    document.write(this.pwd);
  }
}

var Aaron = new User("Aaron", "123");
Aaron.displayAll();

answered Apr 15, 2019 at 7:13

Razana N.

705 bronze badges

Comments

Hien Nguyen · Accepted Answer · 2019-04-15 06:49:31Z

0

You can change from function displayAll() to this.displayAll = function displayAll()

function user(uid, pwd)
    {
        this.uid = uid
        this.pwd = pwd
        this.displayAll = function displayAll()
        {
            document.write(uid)
            document.write(pwd)
        }
    }

    var Aaron = new user("Aaron", "123")

    document.write(Aaron.uid)
    Aaron.displayAll();

answered Apr 15, 2019 at 6:49

Hien Nguyen

19k7 gold badges57 silver badges70 bronze badges

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