If you're not using mongoosejs (which automatically casts the string into ObjectId) then you'd have to cast the string into an ObjectId.
const idToDelete = '5dcc20c3770b9707143301fb'
// if not using mongoose
collection.deleteOne({_id: new mongodb.ObjectID(idToDelete)}, callback};
// if using mongoose > 4 (deleteOne isn't supported on mongoose 4 or higher)
collection.findByIdAndRemove({_id: idToDelete}, callback);
references: https://docs.mongodb.com/manual/reference/method/db.collection.deleteOne/ https://mongoosejs.com/docs/api.html#model_Model.findByIdAndRemove
