How to delete a field in MongoDB

  mongodb, question

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Let me ask, there is only one piece of data in the users table. if I want to delete the indexes 8-11 in the middle cartList item (array), how can I delete these field?
I am not very good at mongoDB just now. By the way, please ask me what are the better mongoDB quick reference materials ~ thank you

db.users.update(
 { _id: ObjectId('58c41d5d3eddd93e9ab5b078') },
 {
 $push: {
 cartList: {
 $each: [ ],
 $slice: 8
 }
 }
 }
 )