Where to handle the error in a sequelize ORM query statement?

Question

I am using Sequelize ORM in Node/Express.

I have two tables, User and Item. Item has a foreign key linked to UserId.

When I try to create an Item with a UserId that is invalid (not present in Users table) a "SequelizeForeignKeyConstraintError" is thrown and leads to crashing of the application due to unhandled.

The problem I have is this:

Where do I handle the error?

Here is my code.

.post(function(req,res){         models.Item.create({             title : req.body.title,             UserId : req.body.UserId         }).then(function(item){             res.json({                 "Message" : "Created item.",                 "Item" : item             });         });     }); 

Answer 1

If you want to handle the specific error, attach a .catch handler

models.Item.create({   title : req.body.title,   UserId : req.body.UserId }).then(function(item){   res.json({     "Message" : "Created item.",     "Item" : item   }); }).catch(function (err) {   // handle error; }); 

If you want to handle errors more generally (i.e. show a nice error message, instead of killing your server, you might want to have a look at unhandledexception

https://nodejs.org/api/process.html#process_event_uncaughtexception

If you are using express, it also contains some error handling facilities http://expressjs.com/en/guide/error-handling.html