How do you use Mongoose without defining a schema?

I think this is what are you looking for Mongoose Strict

option: strict

The strict option, (enabled by default), ensures that values added to our model instance that were not specified in our schema do not get saved to the db.

Note: Do not set to false unless you have good reason.

    var thingSchema = new Schema({..}, { strict: false });
    var Thing = mongoose.model('Thing', thingSchema);
    var thing = new Thing({ iAmNotInTheSchema: true });
    thing.save() // iAmNotInTheSchema is now saved to the db!!

Hey Chris, take a look at Mongous. I was having the same issue with mongoose, as my Schemas change extremely frequently right now in development. Mongous allowed me to have the simplicity of Mongoose, while being able to loosely define and change my 'schemas'. I chose to simply build out standard JavaScript objects and store them in the database like so

function User(user){
  this.name = user.name
, this.age = user.age
}

app.post('save/user', function(req,res,next){
  var u = new User(req.body)
  db('mydb.users').save(u)
  res.send(200)
  // that's it! You've saved a user
});

Far more simple than Mongoose, although I do believe you miss out on some cool middleware stuff like "pre". I didn't need any of that though. Hope this helps!!!

Actually "Mixed" (Schema.Types.Mixed) mode appears to do exactly that in Mongoose...

it accepts a schema-less, freeform JS object - so whatever you can throw at it. It seems you have to trigger saves on that object manually afterwards, but it seems like a fair tradeoff.

Mixed

An "anything goes" SchemaType, its flexibility comes at a trade-off of it being harder to maintain. Mixed is available either through Schema.Types.Mixed or by passing an empty object literal. The following are equivalent:

var Any = new Schema({ any: {} });
var Any = new Schema({ any: Schema.Types.Mixed });

Since it is a schema-less type, you can change the value to anything else you like, but Mongoose loses the ability to auto detect and save those changes. To "tell" Mongoose that the value of a Mixed type has changed, call the .markModified(path) method of the document passing the path to the Mixed type you just changed.

person.anything = { x: [3, 4, { y: "changed" }] };
person.markModified('anything');
person.save(); // anything will now get saved

• Mongoose Schema Types