Dfyjkt

In my Node.js Express application, when the user is logged in via passport the user user object is saved in the request.

It looks something like this:

 "uuid": "caa5cb58-ef92-4de5-a419-ef1478b05dad",
 "first_name": "Sam",
 "last_name": "Smith",
 "email": "sam@email.com",
 "password": "$2a$10$fXYBeoK6s.A8xo2Yfgx4feTLRXpdvaCykZxr7hErKaZDAVeplk.WG",
 "profile_uuid": "db172902-f3c9-456d-8814-53d07d4ea954",
 "isActive": true,
 "deactivate": false,
 "verified": true,
 "ProviderUuid": "7149f8f1-0208-41db-a78e-887e7811a169"

But not every user has the ProviderUuid key present. So before using its value I am trying to check if the ProviderUuid key is present in the user object

var user = req.user;
console.log('---- provider: ' + JSON.stringify(user));
console.log('--- prop: ' + user.hasOwnProperty('ProviderUuid')); //returns false
console.log('---- other method prop check: ' + Object.prototype.hasOwnProperty.call(user, "ProviderUuid")); //returns false
if('ProviderUuid' in user)
 //this returns true

So doing user.hasOwnProperty('ProviderUuid') and Object.prototype.hasOwnProperty.call(user, "ProviderUuid")) returns false, however 'ProviderUuid' in user returns true.

What am I missing here?

Since in works, the property must an inherited property, on one of user's prototype objects, rather than being on user itself. Here's a live example of such behavior:

const userProto = foo: 'bar' ;

// Create an empty object named `user` whose internal prototype is `userProto`:
const user = Object.create(userProto);

// False, user itself is an empty object, nothing's been assigned to it:
console.log(
 user.hasOwnProperty('foo')
);

// True, `foo` does exist on the *internal prototype* of the `user` object:
console.log(
 'foo' in user
);

// True, `foo` is a property directly on `userProto`:
console.log(
 userProto.hasOwnProperty('foo')
);

So, if you want to check for the existence of an inherited property named ProviderUuid, use the in operator like you're doing.

I tested code and all checks returned true.

var user = 
 "uuid": "caa5cb58-ef92-4de5-a419-ef1478b05dad",
 "first_name": "Sam",
 "last_name": "Smith",
 "email": "sam@email.com",
 "password": "$2a$10$fXYBeoK6s.A8xo2Yfgx4feTLRXpdvaCykZxr7hErKaZDAVeplk.WG",
 "profile_uuid": "db172902-f3c9-456d-8814-53d07d4ea954",
 "isActive": true,
 "deactivate": false,
 "verified": true,
 "ProviderUuid": "7149f8f1-0208-41db-a78e-887e7811a169"
;
console.log('---- provider: ' + JSON.stringify(user));
console.log('--- prop: ' + user.hasOwnProperty('ProviderUuid')); //returns false
console.log('---- other method prop check: ' + Object.prototype.hasOwnProperty.call(user, "ProviderUuid")); //returns false
if('ProviderUuid' in user)
 //this returns true

Try JSON.parse(), Maybe req.user saved as string