mongoose/mongodb custom sort

Question

mongoose/mongodb custom sort

I have a field in MongoDB that is a String type. It will contain some combination of letters and numbers like "10", "101", "11", "112", "x115", "abc.5". Right now if I tell MongoDB to sort these it will do an alphabetical sort, ordering as so:

10
101
11
112
abc.5
x115

It orders "101" before "11", how could I change the sorting so that numerals are ordered properly?

node.js
mongodb
mongoose

Answer 1

You might want to use db.eval if you are determined to do this on the database-side.

Answer extracted from another question:

I don't think this is possible directly; the sort documentation certainly doesn't mention any way to provide a custom compare function.

You're probably best off doing the sort in the client, but if you're really determined to do it on the server you might be able to use db.eval() to arrange to run the sort on the server (if your client supports it).

Server-side sort:
db.eval(function() { 
  return db.scratch.find().toArray().sort(function(doc1, doc2) { 
    return doc1.a - doc2.a 
  }) 
});
Versus the equivalent client-side sort:
db.scratch.find().toArray().sort(function(doc1, doc2) { 
  return doc1.a - doc2.b 
});