Added the sort option, first test done

lib/cursor.js

@@ -12,7 +12,7 @@ var model = require('./model');
  */
 function Cursor (db, query) {
   this.db = db;
-  this.query = query;
+  this.query = query || {};
 }
 
 
@@ -20,7 +20,16 @@ function Cursor (db, query) {
  * Set a limit the number of results
  */
 Cursor.prototype.limit = function(limit) {
-  this.limit = limit;
+  this._limit = limit;
+};
+
+
+/**
+ * Sort results of the query
+ * @Param {SortQuery} sortQuery - SortQuery is { field: order }, field can use the dot-notation, order is 1 for ascending and -1 for descending
+ */
+Cursor.prototype.sort = function(sortQuery) {
+  this._sort = sortQuery;
 };
 
 
@@ -30,7 +39,7 @@ Cursor.prototype.limit = function(limit) {
  */
  Cursor.prototype.exec = function(callback) {
   var candidates = this.db.getCandidates(this.query)
-    , res = [], added = 0
+    , res = [], added = 0, self = this
     , i
     ;
   
@@ -38,14 +47,26 @@ Cursor.prototype.limit = function(limit) {
     for (i = 0; i < candidates.length; i += 1) {
       if (model.match(candidates[i], this.query)) {
         res.push(model.deepCopy(candidates[i]));
+        
+        if (!this._sort) {   // If a sort is defined, wait for the results to be sorted before applying limit and skip
           added += 1;
-        if (this.limit && this.limit <= added) { break; }
+          if (this._limit && this._limit <= added) { break; }        
+        }
       }
     }
   } catch (err) {
     return callback(err);
   }
 
+  // Apply all sorts
+  if (this._sort) {
+    Object.keys(this._sort).forEach(function(key) {
+      res.sort(function(a, b) {
+        return self._sort[key] * model.compareThings(model.getDotValue(a, key), model.getDotValue(b, key));
+      });
+    });
+  }
+
   return callback(null, res);
 };
 

lib/datastore.js

@@ -219,6 +219,8 @@ Datastore.prototype.updateIndexes = function (oldDoc, newDoc) {
  * We try the following query types, in this order: basic match, $in match, comparison match
  * One way to make it better would be to enable the use of multiple indexes if the first usable index
  * returns too much data. I may do it in the future.
+ *
+ * TODO: needs to be moved to the Cursor module
  */
 Datastore.prototype.getCandidates = function (query) {
   var indexNames = Object.keys(this.indexes)

test/cursor.test.js

@@ -0,0 +1,78 @@
+var should = require('chai').should()
+  , assert = require('chai').assert
+  , testDb = 'workspace/test.db'
+  , fs = require('fs')
+  , path = require('path')
+  , _ = require('underscore')
+  , async = require('async')
+  , model = require('../lib/model')
+  , Datastore = require('../lib/datastore')
+  , Persistence = require('../lib/persistence')
+  , Cursor = require('../lib/cursor')
+  ;
+
+
+describe.only('Cursor', function () {
+  var d;
+
+  beforeEach(function (done) {
+    d = new Datastore({ filename: testDb });
+    d.filename.should.equal(testDb);
+    d.inMemoryOnly.should.equal(false);
+
+    async.waterfall([
+      function (cb) {
+        Persistence.ensureDirectoryExists(path.dirname(testDb), function () {
+          fs.exists(testDb, function (exists) {
+            if (exists) {
+              fs.unlink(testDb, cb);
+            } else { return cb(); }
+          });
+        });
+      }
+    , function (cb) {
+        d.loadDatabase(function (err) {
+          assert.isNull(err);
+          d.getAllData().length.should.equal(0);
+          return cb();
+        });
+      }
+    ], done);
+  });
+  
+  describe('Sorting of the results', function () {
+  
+    it('Using one sort', function (done) {
+      var cursor, i;
+      
+      d.insert({ age: 5 });
+      d.insert({ age: 57 });
+      d.insert({ age: 52 });
+      d.insert({ age: 23 });
+      d.insert({ age: 89 }, function (err) {   // We only need the last callback as all operations are queued
+        cursor = new Cursor(d, {});
+        cursor.sort({ age: 1 });
+        cursor.exec(function (err, docs) {
+          assert.isNull(err);
+          // Results are in ascending order
+          for (i = 0; i < docs.length - 1; i += 1) {
+            assert(docs[i].age < docs[i + 1].age)
+          }
+          
+          cursor.sort({ age: -1 });
+          cursor.exec(function (err, docs) {
+            assert.isNull(err);
+            // Results are in descending order
+            for (i = 0; i < docs.length - 1; i += 1) {
+              assert(docs[i].age > docs[i + 1].age)
+            }
+          
+            done();
+          });          
+        });
+      });
+    });
+  
+  });
+  
+});