node.js - Auto-increment in Native MongoDB -

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yeah, might here thinking "this rather duplicated question", might indeed, after couple hours searching answer of problem, fail find 1 single answer solve problems, , honest of people asked same thing. i'm gonna try make different question, here goes.

has manage port function below described in mongo doco mongodb native driver? i'm using nodejs , i'm having hard time trying port it's native driver. 

function insertdocument(doc, targetcollection) {      while (1) {          var cursor = targetcollection.find( {}, { _id: 1 } ).sort( { _id: -1 } ).limit(1);          var seq = cursor.hasnext() ? cursor.next()._id + 1 : 1;          doc._id = seq;          targetcollection.insert(doc);          var err = db.getlasterrorobj();          if( err && err.code ) {             if( err.code == 11000 /* dup key */ )                 continue;             else                 print( "unexpected error inserting data: " + tojson( err ) );         }          break;     } }

i read nextobject(), toarray(), foreach() , etc. still can't port it.

has managed make happened function? i'm looking real answer, know lot of people might interested.

i'm asking 1 in particular, because understanding 1 "safe" 1 use other suggestions has flaws when trying insert multiple documents @ same time.

and no, not unique id, i'm still using objectid, need serial number, unique every record.

if have done it, please share!!! save me loooootttt of time! :)

thanks

try this:

function insertdocument(doc, collection) {     collection.find({}, {         limit: 1,         fields: {             _id: 1         },         sort: {             _id: -1         }     }).toarray(function (err, docs) {         var _next = docs.length ? docs[0]._id + 1 : 1;         doc._id = _next;         collection.insert(doc, function (err, result) {             if (err && err.message.indexof('11000') > -1) {                 //try again                 insertdocument(doc, collection);             }         });     });  }

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