fix: handle autopopulate within nested document array when top-level …

…array is empty

Fix #70

index.js

@@ -60,8 +60,9 @@ module.exports = function(schema) {
       }
       autopopulateHandler.call(this, options => {
         const pop = this.populated(options.path);
-        if (pop != null) {
-          return Array.isArray(pop) && pop.length !== this.get(options.path).length;
+        if (Array.isArray(pop)) {
+          const docVal = this.get(options.path);
+          return docVal == null || pop.length !== docVal.length;
         }
         return true;
       });

package.json

@@ -27,7 +27,7 @@
     "co": "4.6.0",
     "co-mocha": "1.2.2",
     "mocha": "5.1.1",
-    "mongoose": "~5.3",
+    "mongoose": "5.x",
     "nyc": "11.7.3"
   },
   "peerDependencies": {

test/bugs.test.js

@@ -11,13 +11,26 @@ describe('bug fixes', function() {
   let db;
 
   before(function() {
-    db = mongoose.createConnection('mongodb://localhost:27017/autopopulate');
+    db = mongoose.createConnection('mongodb://localhost:27017/autopopulate', {
+      useUnifiedTopology: true,
+      useNewUrlParser: true
+    });
   });
 
   after(function(done) {
     db.close(done);
   });
 
+  beforeEach(function() {
+    const promises = [];
+    for (const modelName of Object.keys(db.models)) {
+      const Model = db.model(modelName);
+      promises.push(Model.deleteMany({}));
+    }
+
+    return Promise.all(promises);
+  });
+
   it('gh-15', function(done) {
     const opts = {
       timestamps: { createdAt: 'createdAt' },
@@ -202,4 +215,34 @@ describe('bug fixes', function() {
       assert.equal(docs[0].items[0].name, 'test');
     });
   });
+
+  it('handles autopopulate in nested doc array when top-level array is empty (gh-70)', function() {
+    const User = db.model('User', Schema({ name: String }));
+    db.model('Card', Schema({ name: String }));
+    const GameSchema = new Schema({
+      players: [{
+        type: 'ObjectId',
+        ref: 'User',
+        autopopulate: true
+      }],
+      state: [{
+        cards: [{
+          card: { type: 'ObjectId', ref: 'Card', autopopulate: true }
+        }]
+      }]
+    });
+    GameSchema.plugin(autopopulate);
+    const Game = db.model('Game', GameSchema);
+
+    return co(function*() {
+      const player = yield User.create({ name: 'test' });
+      yield Game.create({ players: [], state: [] });
+
+      const doc = yield Game.findOne();
+      doc.players.push(player._id);
+      yield doc.save();
+
+      assert.deepEqual(doc.toObject().state, []);
+    });
+  });
 });