Mongo query doesn't include my filter clause

Question

Mongo query doesn't include my filter clause

I am building a mongo query in node as such:

query = {"status":{$ne:"Complete"}}, {"processId":1, "_id":0};

then I execute the query:

return this.engine.dbcollectionName.find(query).toArray(function(err, result){...

If i evaluate "conditions", the result is 'status=$ne:"Complete"'...however, my projection is missing.

Am I missing something about how to represent json in javascript variable? It is acting like I didn't include anything after the comma.

Another way to say it, in mongo CLI I want: db.collection.find( {"status":{$ne:"Complete"}}, {"processId":1, "_id":0})

whereas within node, i'm getting equivalent of (notice no projection): db.collection.find( {"status":{$ne:"Complete"}})

Any help appreciated! Thanks

javascript
node.js
mongodb

Answer 1

Your query and projection must be separate object parameters to find:

var query = {"status":{$ne:"Complete"}};
var projection = {"processId":1, "_id":0};
this.engine.dbcollectionName.find(query, projection).toArray(function(err, result){...

Answer 2

New to JavaScript I see. If you want to construct an array of arguments then you need an actual array, and with the way method signatures work here you will also need the JavaScript .apply() method:

var async = require('async'),
    mongodb = require('mongodb'),
    MongoClient = mongodb.MongoClient;


MongoClient.connect('mongodb://localhost/test',function(err,db) {

  var query = [{ "status": { "$ne": "Complete" } }, { "processId": 1, "_id": 0 } ];

  db.collection('collectionname',function(err,coll) {
    coll.find.apply(coll,query).toArray(function(err,docs) {
      if (err) throw err;
      console.log( JSON.stringify( docs, undefined, 2 ) );
    });
  });
});

Otherwise you are separating arguments like

    coll.find.(
       { "status": { "$ne": "Complete" } }, 
       { "processId": 1, "_id": 0 }
    ).toArray(function(err,docs) {

So that each item is passed to the function individually.

.apply() lets you pass in list variables or arrays of arguments to your function. It often requires a context as the first argument, which in this case is the "collection" object that the .find() method belongs to.