Fix for https://github.com/strongloop/loopback/issues/1401

lib/include.js

@@ -1,5 +1,6 @@
 var async = require('async');
 var utils = require('./utils');
+var List = require('./list');
 var isPlainObject = utils.isPlainObject;
 var defineCachedRelations = utils.defineCachedRelations;
 
@@ -734,6 +735,9 @@ Inclusion.include = function (objects, include, options, cb) {
        */
       function setIncludeData(result, cb) {
         if (obj === inst) {
+          if (Array.isArray(result) && !(result instanceof List)) {
+            result = new List(result, relation.modelTo);
+          }
           obj.__data[relationName] = result;
           obj.setStrict(false);
         } else {

test/include.test.js

@@ -1,6 +1,9 @@
 // This test written in mocha+should.js
 var should = require('./init.js');
 var async = require('async');
+var assert = require('assert');
+
+var DataSource = require('../').DataSource;
 
 var db, User, Profile, AccessToken, Post, Passport, City, Street, Building, Assembly, Part;
 
@@ -690,3 +693,95 @@ function clearAndCreate(model, data, callback) {
     itemIndex++;
   }
 }
+
+describe('Model instance with included relation .toJSON()', function() {
+  var db, ChallengerModel, GameParticipationModel, ResultModel;
+
+  before(function(done) {
+    db = new DataSource({connector: 'memory'});
+    ChallengerModel = db.createModel('Challenger',
+      {
+        name: String
+      },
+      {
+        relations: {
+          gameParticipations: {
+            type: 'hasMany',
+            model: 'GameParticipation',
+            foreignKey: ''
+          }
+        }
+      }
+    );
+    GameParticipationModel = db.createModel('GameParticipation',
+      {
+        date: Date
+      },
+      {
+        relations: {
+          challenger: {
+            type: 'belongsTo',
+            model: 'Challenger',
+            foreignKey: ''
+          },
+          results: {
+            type: 'hasMany',
+            model: 'Result',
+            foreignKey: ''
+          }
+        }
+      }
+    );
+    ResultModel = db.createModel('Result', {
+      points: Number,
+    }, {
+      relations: {
+        gameParticipation: {
+          type: 'belongsTo',
+          model: 'GameParticipation',
+          foreignKey: ''
+        }
+      }
+    });
+
+    async.waterfall([
+      createChallengers,
+      createGameParticipations,
+      createResults],
+      function(err) {
+        done(err);
+      });
+
+  });
+
+  function createChallengers(callback) {
+    ChallengerModel.create([{name: 'challenger1'}, {name: 'challenger2'}], callback);
+  }
+
+  function createGameParticipations(challengers, callback) {
+    GameParticipationModel.create([
+      {challengerId: challengers[0].id, date: Date.now()},
+      {challengerId: challengers[0].id, date: Date.now()}
+    ], callback);
+  }
+
+  function createResults(gameParticipations, callback) {
+    ResultModel.create([
+      {gameParticipationId: gameParticipations[0].id, points: 10},
+      {gameParticipationId: gameParticipations[0].id, points: 20}
+    ], callback);
+  }
+
+  it('should recursively serialize objects', function(done) {
+    var filter = {include: {gameParticipations: 'results'}};
+    ChallengerModel.find(filter, function(err, challengers) {
+
+      var levelOneInclusion = challengers[0].toJSON().gameParticipations[0];
+      assert(levelOneInclusion.__data === undefined, '.__data of a level 1 inclusion is undefined.');
+
+      var levelTwoInclusion = challengers[0].toJSON().gameParticipations[0].results[0];
+      assert(levelTwoInclusion.__data === undefined, '__data of a level 2 inclusion is undefined.');
+      done();
+    });
+  });
+});