How to query mongoose by property that is and array item

Question

How to query mongoose by property that is and array item

I have a mongoose model that looks like this:

var mongoose = require('mongoose')
, Schema = mongoose.Schema;

var PictureSchema = new Schema({
    listId: { type: Array, required: true },
    thumb: { type: String, required: true },
    large: { type: String, required: true }
});

var Picture = module.exports = mongoose.model('Picture', PictureSchema);

I am trying to update instances of this model in my router by looking up a Picture via the "listId" property. Like this:

app.put('/pictures/append', function(req, res) {
  var targetListId = req.body.targetListId
    , currentListId = req.body.currentListId;

  Picture
    .find({ listId: currentListId }, function (err, picture) {
      console.log('found pic', picture);
      picture.listId.push(targetListId);
      picture.save(function(err, pic) {
        console.log('pic SAVED', pic);
      });
    });
});

"currentListId" is a string, and listId is an array of currentListId's. Maybe this isn't the correct way to query a a property that is an array? I am getting an error:

TypeError: Cannot call method 'push' of undefined

On the line:

picture.listId.push(targetListId);

But when I look up the picture models in mongo, they DO have listId arrays and some DO contain the item "currentListId" that I am using for my query.

I tried using $elemMatch and $in but I don't know if I was using them correctly. Any idea if I am just writing my query wrong?

arrays
node.js
mongodb
mongoose

Answer 1

Specifying an Array typed field in your schema is equivalent to Mixed which tells Mongoose that field could contain anything. Instead, change your schema to something like this:

var PictureSchema = new Schema({
    listId: [String],
    thumb: { type: String, required: true },
    large: { type: String, required: true }
});