My Modal :

{
  "name":{type:String,required:true},
  "category":{type:mongoose.Schema.Types.ObjectId,ref:"Category"}
}

I have a document created using this modal and the document looks like:

{
  "_id":ObjectId("5dsfkjh2r74dsjdhf3r4f"),
  "name":"demo 1",
  "category":ObjectId("5ae9dlkj32nds6n37cj23")
}

If I try to change the category field, for eg:

• document.category = ''
• document.category = null
• document.category = undefined

I'm getting the following error:

Cast toObjectId failed ...

I need to unset the "category" field to null or empty or even delete it. How to do that?

My Modal :

{
  "name":{type:String,required:true},
  "category":{type:mongoose.Schema.Types.ObjectId,ref:"Category"}
}

I have a document created using this modal and the document looks like:

{
  "_id":ObjectId("5dsfkjh2r74dsjdhf3r4f"),
  "name":"demo 1",
  "category":ObjectId("5ae9dlkj32nds6n37cj23")
}

If I try to change the category field, for eg:

• document.category = ''
• document.category = null
• document.category = undefined

I'm getting the following error:

Cast toObjectId failed ...

I need to unset the "category" field to null or empty or even delete it. How to do that?

• javascript
• node.js
• mongodb
• mongoose

3 Answers 3

Try unsetting the document

document.update({_id: "5dsfkjh2r74dsjdhf3r4f"}, {$unset: {category: 1 }});

or

document.update({_id: ObjectId("5dsfkjh2r74dsjdhf3r4f")}, {$unset: {category: 1 }});

ObjectId should be a 24 length string which I guess your id is not. That's why mongo cannot convert it into valid ObjectId.

One solution would be to generate 24 character valid ObjectId for category field. Other would be to set category as a simple String instead of ObjectId

Use Below line document.category = new MongoDB\BSON\ObjectID('');