猫鼬在自定义_id上无法正常工作

Question

For whatever reason, mongoose seems to be unable to actually locate my document after a find call because of a custom ID.

The source of the problem:

// ...
models.Item.findOne().where({ _id: item.id }).exec((i) => {
  console.log(item.id, i);
  if (!i) i = new models.Item({ _id: item.id, href: item.href, name: item.name });
  // ...

The console just logs the following:

> 0 null
> MongoError: E110000 duplicate key error index: items.$_id_  dup key: { : 0 }

Indicating it seems to be unable to locate the document with the ID zero, but immediately follows up by complaining the key already exists with a value of 0 when I try to create a new one.

Upon looking at the database, I can clearly see my document with an _id of 0.

{
  "id": 0,
  // ...
}

And this is the schema I'm using:

const ItemSchema = new mongoose.Schema({
  _id: { type: Number, min: 0, max: 400000, unique: true, required: true },
  // ...
}

I've tried find and findOne in the chained and un-chained versions and findById . None of them are yeilding the existing document. Why?

Answer 1

You're missing the error parameter in your exec callback. It should be:

models.Item.findOne().where({ _id: item.id }).exec((err, i) => {...

The second parameter is the document result.