title: Cannot use Mongodb distinct in Nodejs
body: <p>I am having a problem when I am trying to get all distinct values from a field("acc") in a collection</p>
  
  <pre><code>var mongojs = require('mongojs');
  var mongodb = mongojs('mongodb://localhost:27017/na');
  var mongodb_data = mongodb.collection('data');
  
  
  mongodb_data.distinct(
     "acc",
     (function(err, docs){
          if(err){
              return console.log(err);
          }
          if(docs){  
              console.log(docs);
          }
     })
  );
  </code></pre>
  
  <p>When I run the code, it gave the error traces below</p>
  
  <pre><code>(node:45480) DeprecationWarning: sys is deprecated. Use util instead.
  /.../node_modules/mongodb/lib/utils.js:98
  process.nextTick(function() { throw err; });
                                ^
  TypeError: cb is not a function
      at /U.../node_modules/mongojs/lib/collection.js:69:5
      at handleCallback (/.../node_modules/mongodb/lib/utils.js:95:56)
      at /.../node_modules/mongodb/lib/db.js:313:5
      at /.../node_modules/mongodb-core/lib/connection/pool.js:455:18
      at _combinedTickCallback (internal/process/next_tick.js:67:7)
      at process._tickCallback (internal/process/next_tick.js:98:9)
  </code></pre>