CODEWITHSUNDEEP
node.jsmongodbexpress
Drewsdesign
Drewsdesign

Reputation: 61

Nodejs undefined variable

I have an empty database and im getting TypeError: Cannot read property 'id' of undefined

Im not sure how to check for a undefined variable, or even if this check should be in the db model

Express route

    app.all("/", function(req, res){  
      if(!req.isAuthenticated()) req.user = null;    
      Bid.findHighestBids(function(err, bids){
        if(err) throw err;
        User.findHighestBidder(bids[0].id, bids[0].amount, function(err, highest){
          if(err) throw err;
          highest.amount = bids[0].amount;  
          res.render("home", {user: req.user, bids: req.bids, highest: highest}); 
        });      
      });
    });

Snippet from the models, (there is no data so its not returning anything, which is the problem)

    BidSchema.statics.findHighestBids = function(done){
      var Bids = this; 
      var num = 5;  
      this.find()
      .sort('-amount')
      .limit(num)
      .exec(function(err,bids){
        if(err) throw err;
        done(null, bids);
      });   
    }

    UserSchema.statics.findHighestBidder = function(id, amount, done){
      var User = this; 
      this.findOne({ 'facebook.id' : id }, function(err, highest){
        if(err) throw err;
        if(!id) return done(null, highest);
        done(null, highest);
      });  
    }

Upvotes: 1

Views: 1281

Answers (1)

JohnnyHK
JohnnyHK

Reputation: 312129

You're not checking that bids contains any elements before accessing the first one. Since you say you have no data, that's likely your problem:

Bid.findHighestBids(function(err, bids){
  if(err) throw err;
  User.findHighestBidder(bids[0].id, bids[0].amount, function(err, highest){
  ...

bids[0] returns undefined, which has no id property, and thus the error.

So do something like this instead:

Bid.findHighestBids(function(err, bids){
  if (err) throw err;
  if (bids.length) {
    User.findHighestBidder(bids[0].id, bids[0].amount, function(err, highest){
      if(err) throw err;
      highest.amount = bids[0].amount;  
      res.render("home", {user: req.user, bids: req.bids, highest: highest}); 
    });      
  } else {
    res.render(... whatever you need for the no bids case ...);
  }

Upvotes: 3

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