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Asked: 2026-06-10T20:31:29+00:00

In a new version on MongoDB we can use an $elemMatch projection operator to

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In a new version on MongoDB we can use an $elemMatch projection operator to limit the response of a query to a single matching element of an array. http://docs.mongodb.org/manual/reference/projection/elemMatch/

But it seems doesn’t work yet in mongoose 3 here is the example:

{
 _id: ObjectId(5), 
 items: [1,2,3,45,4,67,9,4]
}

Folder.findOne({_id: Object(5)}, {$elemMatch: {$in: [1,67,9]}})
  .exec(function (err, doc) {

});

I’m expected to get the follows doc:

{
 _id: ObjectId(5), 
 items: [1,67,9]
}

But unfortunately what I’m getting is document with all items:

{
 _id: ObjectId(5), 
 items: [1,2,3,45,4,67,9,4]
}
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1 Answer

  1. Editorial Team

    The mongodb docs here are misleading, we’ll get them updated.

    What its saying is that you can now use $elemMatch in your projection, that is, your field selection:

    https://gist.github.com/3640687

    See also: https://github.com/learnboost/mongoose/issues/1085

    [Edit] pull request for docs sent: https://github.com/mongodb/docs/pull/185

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