node.js - loopback PersistedModel find() error handling -

i'm following loopback framework tutorial, page https://docs.strongloop.com/display/public/lb/extend+your+api there example code finds instance id, modified bit handle non-existent instances

coffeeshop.getname=function(id, cb) {     coffeeshop.findbyid(id, function(err, shop){         if(err)         {             console.log(err);             cb(err);         }         else                             cb(null, 'name of coffee shop '+shop.name);     }); }; 

it works fine when call existing id, when enter invalid id, instead of calling err handler it's omitted entirely, else statement called , whole app crashes following console error

/app/path/here/node_modules/mysql/lib/protocol/parser.js:78 throw err; // rethrow non-mysql errors 

i'm new node.js , i'm pretty sure i'm missing here shouldn't error passed callback function rather being thrown top level?

this doesn't seem mysql backend specific, switched mongo connector , got similar problem. how handle error properly?

you'll need check shop parameter also. complete check this:

coffeeshop.getname=function(id, cb) {     coffeeshop.findbyid(id, function(err, shop){         if(err)         {             console.log(err);             cb(err);         }         else         {           if(shop) {             cb(null, 'name of coffee shop '+shop.name);           } else {             var error = new error();             error.message = 'coffee shop not found.';             error.statuscode = 404;             cb(error);           }         }                 }); }; 

here pattern loopback uses built-in models. code file node_modules/loopback/common/models/user.js, @ around 281 line number.

user.logout = function(tokenid, fn) { fn = fn || utils.createpromisecallback(); this.relations.accesstokens.modelto.findbyid(tokenid, function(err, accesstoken) {   if (err) {     fn(err);   } else if (accesstoken) {     accesstoken.destroy(fn);   } else {     fn(new error('could not find accesstoken'));   } }); return fn.promise;