Mongoose.js getter that inflates subdocuments on Find()? - json

Question

Is there an inverse of Mongoose.js validation that can inflate the subdocument when the parent is retrieved? I may have been looking at the docs so long I'm not recognizing an existing feature for what it is.
A beauty of MongoDB is that the query specifications (e.g. {likes: {$gt: 10, $le: 14}} are themselves Javascript objects, and until recently have been storing them in a MongoDB instance as subdocuments.
However, upgrading from MongoDB 2.4 to 2.6, these are no longer valid to store as such, and am now getting the error: The dollar ($) prefixed field '$or' ... is not valid for storage
Am thus in the situation in this Google Groups Discussion. The author there suggests flattening the document to a String. This situation can also occur if the subdocuments have legitimate Javascript attributes that have embedded dots (e.g. {"802.11g": ...})
That's easy enough to by specifying JSON.parse and JSON.stringify as the getter/setter in Mongoose.js:
var ProjectSchema = new Schema({
name: { type: String, required: false, default: "New project" },
spec: {type: mongoose.Schema.Types.Mixed, set: JSON.stringify, get: JSON.parse},
});
But the getter only gets called if I explicitly ask for the attribute value. The attribute is still a string underneath and gets passed as such:
Project.findById(req.params.projectId, function(err, project) {
console.log("......"+(typeof project.spec)) // project.spec is an object!
res.send(project); // project.spec is a String!
});
Obviously i can call model.spec = JSON.parse(model.spec) within each Model.find(...) call and for each flattened attribute but it'd be nice to do it at one central location.
https://groups.google.com/forum/?fromgroups=#!topic/mongoose-orm/8AV6aoJzdiQ

Answer 1

You can invoke your getter in res.send by adding the {toJSON: {getters: true}} option to the ProjectSchema definition. You'll probably want to enable that for the toObject option as well for cases like passing the doc to console.log.
var ProjectSchema = new Schema({
name: { type: String, required: false, default: "New project" },
spec: {type: mongoose.Schema.Types.Mixed, set: JSON.stringify, get: JSON.parse},
}, {
toJSON: {getters: true},
toObject: {getters: true}
});
Docs here.