mongoose objectid to number

This is untested, but I think you'd want to do something like this:

var idNum = parseInt(objectId.valueOf(), 16);

MongoDB ObjectIDs are essentially 12 byte hex strings. This makes them larger than the MAX_VALUE for a JavaScript Number (2^53), so you may run into errors with the conversion. But, it looks like Number.MAX_VALUE in my node.js environment (0.11.6) can handle that value. So you might be safe...

Why are you converting an Object ID to a Number though? You really shouldn't be performing arithmetic operations on an ObjectId...

try using the virtual id onstead of _id

option(data-id=val.id) #{val.name}

instead of

option(data-id=val._id) #{val.name}