Add filter.fields support to dao and memory connector

lib/adapters/memory.js

@@ -1,4 +1,5 @@
 var geo = require('../geo');
+var utils = require('../utils');
 
 exports.initialize = function initializeSchema(schema, callback) {
     schema.adapter = new Memory();
@@ -146,11 +147,15 @@ Memory.prototype.all = function all(model, filter, callback) {
             nodes = nodes ? nodes.filter(applyFilter(filter)) : nodes;
         }
         
+        // field selection
+        if(filter.fields) {
+            nodes = nodes.map(utils.selectFields(filter.fields))
+        }
+
         // limit/skip
         filter.skip = filter.skip || 0;
         filter.limit = filter.limit || nodes.length;
         nodes = nodes.slice(filter.skip, filter.skip + filter.limit);
-
     }
 
     process.nextTick(function () {

lib/dao.js

@@ -16,6 +16,7 @@ var Inclusion = require('./include.js');
 var Relation = require('./relations.js');
 var geo = require('./geo');
 var Memory = require('./adapters/memory').Memory;
+var fieldsToArray = require('./utils').fieldsToArray;
 
 /**
  * DAO class - base class for all persist objects
@@ -321,9 +322,16 @@ DataAccessObject.find = function find(params, cb) {
     }
     var constr = this;
     
+    
+    var fields = params && params.fields;
     var near = params && geo.nearFilter(params.where);
     var supportsGeo = !!this.schema.adapter.buildNearFilter;
     
+    // normalize fields as array of included property names
+    if(fields) {
+        params.fields = fieldsToArray(fields, Object.keys(this.properties));
+    }
+    
     if(near) {
       if(supportsGeo) {
         // convert it
@@ -331,10 +339,6 @@ DataAccessObject.find = function find(params, cb) {
       } else if(params.where) {
         // do in memory query
         // using all documents
-        
-        
-        
-        
         this.schema.adapter.all(this.modelName, {}, function (err, data) {
           var memory = new Memory();
           var modelName = constr.modelName;

lib/utils.js

@@ -1,4 +1,6 @@
 exports.safeRequire = safeRequire;
+exports.fieldsToArray = fieldsToArray;
+exports.selectFields = selectFields;
 
 function safeRequire(module) {
     try {
@@ -9,3 +11,59 @@ function safeRequire(module) {
     }
 }
 
+function fieldsToArray(fields, properties) {
+    if(!fields) return;
+  
+    // include all properties by default
+    var result = properties;
+  
+    if(typeof fields === 'string') {
+      return [fields];
+    }
+  
+    if (Array.isArray(fields) && fields.length > 0) {
+        // No empty array, including all the fields
+        return fields;
+    }
+  
+    if ('object' === typeof fields) {
+        // { field1: boolean, field2: boolean ... }
+        var included = [];
+        var excluded = [];
+        var keys = Object.keys(fields);
+        if(!keys.length) return;
+        
+        keys.forEach(function (k) {
+            if (fields[k]) {
+                included.push(k);
+            } else if ((k in fields) && !fields[k]) {
+                excluded.push(k);
+            }
+        });
+        if (included.length > 0) {
+            result = included;
+        } else if (excluded.length > 0) {
+            excluded.forEach(function (e) {
+                var index = result.indexOf(e);
+                result.splice(index, 1);
+            });
+        }
+    }
+    
+    return result;
+}
+
+function selectFields(fields) {
+  // map function
+  return function (obj) {
+    var result = {};
+    var key;
+    
+    for (var i = 0; i < fields.length; i++) {
+      key = fields[i];
+      
+      result[key] = obj[key];
+    }
+    return result;
+  }
+}

test/basic-querying.test.js

@@ -132,6 +132,53 @@ describe('basic-querying', function() {
             });
         });
         
+        it('should only include fields as specified', function(done) {
+            var remaining = 0;
+          
+            function sample(fields) {
+              
+              return {
+                expect: function (arr) {
+                  remaining++;
+                  User.find({fields: fields}, function(err, users) {
+                    
+                      remaining--;
+                      if(err) return done(err);
+                  
+                      should.exists(users);
+                  
+                      if(remaining === 0) {
+                        done();
+                      }
+                
+                      users.forEach(function (user) {
+                        var obj = user.toObject();
+                        
+                        Object.keys(obj)
+                          .forEach(function (key) {
+                            // if the obj has an unexpected value
+                            if(obj[key] !== undefined && arr.indexOf(key) === -1) {
+                              console.log('Given fields:', fields);
+                              console.log('Got:', key, obj[key]);
+                              console.log('Expected:', arr);
+                              throw new Error('should not include data for key: '+ key);
+                            }
+                          });                        
+                      });
+                  });
+                }
+              }
+            }
+            
+            sample({name: true}).expect(['name']);
+            sample({name: false}).expect(['id', 'email', 'role', 'order']);
+            sample({name: false, id: true}).expect(['id']);
+            sample({id: true}).expect(['id']);
+            sample('id').expect(['id']);
+            sample(['id']).expect(['id']);
+            sample(['email']).expect(['email']);
+        });
+
     });
 
     describe('count', function() {

test/util.test.js

@@ -0,0 +1,27 @@
+var should = require('./init.js');
+var fieldsToArray = require('../lib/utils').fieldsToArray;
+
+describe('util.fieldsToArray', function(){
+  it('Turn objects and strings into an array of fields to include when finding models', function() {
+    
+    
+    function sample(fields) {
+      var properties = ['foo', 'bar', 'bat', 'baz'];
+      return {
+        expect: function (arr) {
+          should.deepEqual(fieldsToArray(fields, properties), arr);
+        }
+      }
+    }
+    
+    sample(false).expect(undefined);
+    sample(null).expect(undefined);
+    sample({}).expect(undefined);
+    sample('foo').expect(['foo']);
+    sample(['foo']).expect(['foo']);
+    sample({'foo': 1}).expect(['foo']);
+    sample({'bat': true}).expect(['bat']);
+    sample({'bat': 0}).expect(['foo', 'bar', 'baz']);
+    sample({'bat': false}).expect(['foo', 'bar', 'baz']);
+  });
+});