Javascript Class returns undefined

Question

When using this Code the function returns undefined instead of an object.

function Oauth_User_Profile() {
 this.username = "=";
 this.password = "=";
 this.refresh_token = "=";
 this.access_token = "=";
 this.request = function(url, formData, method, then) {
 var xhttp = new XMLHttpRequest();
 xhttp.onreadystatechange = function() {
 if(xhttp.readyState == 4 && xhttp.status == 200)
 {
 var j = JSON.parse(this.responseText);
 then(j);
 }
 }
 xhttp.open(method, url); 
 xhttp.send(JSON.stringify(formData)); 
 }
}
var oauth_user_profile = Oauth_User_Profile();
oauth_user_profile.username = "sample";

I've got nearly the same Code for other classes which is working fine, so I don't know why this isn't running properly

Duplicate: Question was marked as a duplicate for [How do I return the response from an asynchronous call?. However, I don't want to return the result of the call, I want to return an object which contains username, password, refresh_token... AND a method which can be run. I run into the exact same problem when removing the async-part:

function Oauth_User_Profile() {
 this.username = "=";
 this.password = "=";
 this.refresh_token = "=";
 this.access_token = "=";
}

This still gives the error: Uncaught TypeError: Cannot set property 'username' of undefined at testm.html:67

• Quentin: You forgot to call the constructor function with new
• Maor Refaeli: Just for good standards, in JavaScript we use UpperCamelCase for classes: Oauth_User_Profile => OauthUserProfile and lowerCamelCase for variables and functions: oauth_user_profile => oauthUserProfile

Answer 1

You are missing the new keyword:

var oauth_user_profile = new Oauth_User_Profile();