Ability to get a cursor from a findOne

lib/cursor.js

@@ -9,10 +9,12 @@ var model = require('./model');
  * Create a new cursor for this collection
  * @param {Datastore} db - The datastore this cursor is bound to
  * @param {Query} query - The query this cursor will operate on
+ * @param {Function} execDn - Handler to be executed  after cursor has found the results and before the callback passed to find/findOne/update/remove
  */
-function Cursor (db, query) {
+function Cursor (db, query, execFn) {
   this.db = db;
   this.query = query || {};
+  if (execFn) { this.execFn = execFn; }
 }
 
 
@@ -96,7 +98,11 @@ Cursor.prototype._exec = function(callback) {
     res = res.slice(skip, skip + limit);
   }
 
-  return callback(null, res);
+  if (this.execFn) {
+    return this.execFn(null, res, callback);
+  } else {
+    return callback(null, res);
+  }
 };
 
 Cursor.prototype.exec = function () {

lib/datastore.js

@@ -389,7 +389,10 @@ Datastore.prototype.count = function() {
  * @param {Object} query MongoDB-style query
  */
 Datastore.prototype.find = function (query, callback) {
-  var cursor = new Cursor(this, query);
+  var cursor = new Cursor(this, query, function(err, docs, callback) {
+    if (err) { return callback(err); }
+    return callback(null, docs);
+  });
 
   if (typeof callback === 'function') {
     cursor.exec(callback);
@@ -404,15 +407,21 @@ Datastore.prototype.find = function (query, callback) {
  * @param {Object} query MongoDB-style query
  */
 Datastore.prototype.findOne = function (query, callback) {
-  var cursor = new Cursor(this, query);
-  cursor.limit(1);
-  cursor.exec(function (err, docs) {
-    if (err) {
-      return callback(err);
+  var cursor = new Cursor(this, query, function(err, docs, callback) {
+    if (err) { return callback(err); }
+    if (docs.length === 1) {
+      return callback(null, docs[0]);
     } else {
-      return callback(null, docs.length === 1 ? docs[0] : null);
+      return callback(null, null);    
     }
   });
+
+  cursor.limit(1);
+  if (typeof callback === 'function') {
+    cursor.exec(callback);
+  } else {
+    return cursor;
+  }
 };
 
 

test/cursor.test.js

@@ -531,7 +531,7 @@ describe('Cursor', function () {
         }
       ], done);
     });
-    
+
     it('Multiple consecutive sorts', function(done) {
       async.waterfall([
         function (cb) {

test/db.test.js

@@ -620,7 +620,42 @@ describe('Database', function () {
         });      
       });
     });
-    
+
+     it('Can use sort and skip if the callback is not passed to findOne but to exec', function (done) {
+      d.insert({ a: 2, hello: 'world' }, function () {
+        d.insert({ a: 24, hello: 'earth' }, function () {
+          d.insert({ a: 13, hello: 'blueplanet' }, function () {
+            d.insert({ a: 15, hello: 'home' }, function () {
+              // No skip no query
+              d.findOne({}).sort({ a: 1 }).exec(function (err, doc) {
+                assert.isNull(err);
+                doc.hello.should.equal('world');
+                
+                // A query
+                d.findOne({ a: { $gt: 14 } }).sort({ a: 1 }).exec(function (err, doc) {
+                  assert.isNull(err);
+                  doc.hello.should.equal('home');
+                  
+                  // And a skip
+                  d.findOne({ a: { $gt: 14 } }).sort({ a: 1 }).skip(1).exec(function (err, doc) {
+                    assert.isNull(err);
+                    doc.hello.should.equal('earth');
+                    
+                    // No result
+                    d.findOne({ a: { $gt: 14 } }).sort({ a: 1 }).skip(2).exec(function (err, doc) {
+                      assert.isNull(err);
+                      assert.isNull(doc);
+                      
+                      done();
+                    });
+                  });
+                });
+              });
+            });
+          });
+        });      
+      });
+    });   
 
   });   // ==== End of 'Find' ==== //