如果不在新文档中，Upsert会删除该字段

Question

Let's assume the following model (note strict:false ):

var Test = db.model('Test', {
  a: {type: String, required: true},
  b: {type: String}
}, {strict: false});

and I currently have this document in the database:

{
  'a': 'hello',
  'b': 'world',
  'c': {
       'x': 'embedded',
       'z': 'document' 
     }
}

If I upsert the following document:

doc = {
  'a': 'hello',
  'b': 'jack'
}

with something like:

Test.findOneAndUpdate({
  a: 'hello'
}, doc, {upsert:true}, function(){});

I will end up with:

{
  'a': 'hello',
  'b': 'jack'
}

In other words, a field c that is not present in the upserted document is wiped.

How can I safely upsert without wiping such fields?

Answer 1

Strange, this should work as is. Maybe you can try explicitly setting fields:

doc = {$set: {
  'a': 'hello',
  'b': 'jack'
}};