TypeError：无法读取password.js中未定义的属性“用户名”

Question

  app.get('/getUser', function(req, res) {

     console.log(req.user.username);

         res.json({'user':req.user.username}); 
    });

When I login to passportjs, this does not return any error, but when I am not logged in, it shows TypeError: Cannot read property 'username' of undefined error, I need to send res.json only if it is defined,

     app.get('/getUser', function(req, res) {

         console.log(req.user.username);
    if(typeof req.user.username!="undefined")
             res.json({'user':req.user.username}); 
           else
     res.json({'user':"Anonymous"}); 
                    });

but it gives error for conditional statement, How do I error handle it?

Answer 1

Passport places user on the req object. If you have not performed authentication with Passport, there will be no user object on the request object. Therefore, req.user will be undefined. As you can probably imagine, undefined does not have a property named username, causing your error.

You probably want something like:

username = req.user ? req.user.username : "Anonymous"
res.json({'user':username});