How to remove subdocument inside of a object using Mongoose

Question

I'm trying to remove subdocument with ID from Object using Mongoose. I was trying to use update fucntion in Moongose but after i run script Im getting status "Ok: 1" but status "nModified: 0". Was trying to use following script:

 Page.update({"subPages._id": req.body.ID}, {"$unset":{"subPages":1}}, function (re,q) {
    console.log(q);
});

This script removes all subdocuments from a object. Here is my json:

{
"_id" : ObjectId("585a7a7c2ec07b40ecb093d6"),
"name_en" : "Head Page",
"name_nl" : "Head Page",
"slug_en" : "Head-page",
"slug_nl" : "hoofd-menu",
"content_en" : "<p>Easy (and free!) You should check out our premium features.</p>",
"content_nl" : "<p>Easy (and free!) You should check out our premium features.</p>",
"date" : ISODate("2016-12-21T12:50:04.374Z"),
"is_footerMenu" : 0,
"is_headMenu" : 0,
"visible" : 1,
"__v" : 0,
"subPages" : [ 
    {
        "content_nl" : "<p>Easy (and free!) You should check out our premium features.</p>",
        "content_en" : "<p>Easy (and free!) You should check out our premium features.</p>",
        "slug_nl" : "Sub-page",
        "slug_en" : "Sub-page",
        "name_nl" : "Subpage",
        "name_en" : "Subpage",
        "date" : ISODate("2016-12-21T14:58:44.733Z"),
        "subPages" : [],
        "is_footerMenu" : 0,
        "is_headMenu" : 0,
        "visible" : 1,
        "_id" : ObjectId("585a98a46f657b52489087a8")
    }, 
    {
        "content_nl" : "<p>Easy (and free!) You should check out our premium features.</p>",
        "content_en" : "<p>Easy (and free!) You should check out our premium features.</p>",
        "slug_nl" : "Subpage",
        "slug_en" : "Subpage",
        "name_nl" : "Subpage1",
        "name_en" : "Subpage1",
        "date" : ISODate("2016-12-21T14:58:54.819Z"),
        "subPages" : [],
        "is_footerMenu" : 0,
        "is_headMenu" : 0,
        "visible" : 1,
        "_id" : ObjectId("585a98ae6f657b52489087a9")
    }
]

}

I want to remove subobject with ID

585a98a46f657b52489087a8

How can I do it?

Answer 1

In order to remove an element (subdocument) from an array you need to $pull it.

Page.update({
  'subPages._id': req.body.ID
}, {
  $pull: { subPages: { _id: req.body.ID } }
}, function (error, result) {
    console.log(result);
});

If you want to remove all subdocuments (ie make the subPages to be empty), you can $set its value to be an empty array.

Page.update({
  'subPages._id': req.body.ID
}, {
  $set: { subPages: [] }
}, function (error, result) {
    console.log(result);
});

Hope it helps.