Mongoose. Remove fields on save that are not present in schema

Question

I have a doc saved in MongoDB like this:

{
  title: 'title',
  author: 'author name',
  body: 'the body',
  admin: 'admin user'
}

And this is the schema in Mongoose:

var blogSchema = new Schema({
  title:  String,
  author: String,
  body:   String
});

I would like that on save, the "admin" field was removed from the doc, is this possible? Can I automatize this in event pre-save?

Thanks.

Can you show how you are saving the blog. Ideally it should not save admin field if it is not defined in the schema — Ravi Shankar Bharti, Apr 19 '17 at 06:13
So, You need to returned the saved doc back to client but You do not want to show the admin field, right ? — thelonglqd, Apr 19 '17 at 07:05
Nop, the document was previously saved in the database with other mechanism, and now the admin field is not necessary... — chemitaxis, Apr 19 '17 at 07:19

score 8 · Accepted Answer · edited May 23 '17 at 11:46

Ok, the correct way of removing a field that is not present in the Schema and is present in the document is:

doc.set('field', undefined, { strict: false }) // strict is default true, you need to add if you are using strict mode

You can use it for example in your middlewares, in my case in the pre-save middleware.

I found the answer in a comment in this question.

I can't find an automatize mode yet.

Shining Love Star · Answer 2 · 2022-11-26T08:29:17.590

0

While the suggested answer might work (didn't test myself), there's a more versatile solution to allow multiple fields and documents with one call:

const fields = ["admin"];
const unset = fields.reduce(
  (acc, field) => ({
    ...acc,
    [field]: 1,
  }),
  {}
);

YourModel.collection.updateMany(query, { $unset: unset });

edited Nov 26 '22 at 08:29

answered Nov 26 '22 at 07:11

Shining Love Star

5,734
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score 0 · Answer 3 · answered Jun 27 '23 at 07:02

0

Try turning off strict mode in your update and it should work though:

User.update({}, {$unset: {someField: 1}}, {multi: true, strict: false});

original answer was taken from this issue

answered Jun 27 '23 at 07:02

Jubair

11
2

Mongoose. Remove fields on save that are not present in schema

3 Answers3