node.js - I want to delete the author with its _id. While querying its not showing any error but deletion does not take place from the database -

here using promised-mongo. while querying working fine particular data doesnot gets deleted database. can me?

 const mutation = new graphqlobjecttype({     name: "mutations",     fields: {       deletedonor: {       type: donor,       args: {         _id: { type: graphqlstring }       },       resolve: function(rootvalue, args) {         let donor = object.assign({}, args);         return donorscollection.remove({_id:donor._id})           .then(_ => donor);       }     }     } });