nl_tokens: Either insert update or delete the given records from the fhsync - <datasetId > - records collection .
pl_tokens: function upsertOrDeleteDatasetRecords ( datasetId , datasetClientId , records , cb ) { var datasetRecordsCol = mongoClient . collection ( getDatasetRecordsCollectionName ( datasetId ) ) ; debug ( 'upsertOrDeleteDatasetRecords diff records = %j' , records ) ; async . mapLimit ( records , RECORDS_UPDATE_CONCURRENCY , function ( record , callback ) { var op = record . op ; var fields = { uid : record . uid , hash : record . hash , data : record . data } ; var <mask> = { '$set' : fields } ; if ( op === 'update' ) { //$addToSet only adds the value to the array if it doesn't exist update [ '$addToSet' ] = { 'refs' : datasetClientId } ; } else if ( op === 'delete' ) { //remove the ref update [ '$pull' ] = { 'refs' : datasetClientId } ; } datasetRecordsCol . findOneAndUpdate ( { uid : record . uid } , update , { upsert : true , returnOriginal : false } , function ( err , updated ) { if ( err ) { return callback ( err ) ; } else { return callback ( null , updated . value ) ; } } ) ; } , function ( err , updates ) { if ( err ) { debugError ( 'Failed to upsertOrDeleteDatasetRecords due to error %s :: datasetId = %s' , err , datasetId ) ; return cb ( err ) ; } var returned = _ . compact ( updates ) ; return cb ( null , returned ) ; } ) ; }