Merge branch 'ryanxwelch-remove_duplicate_includes'

lib/serializer.js

@@ -379,7 +379,25 @@ function handleIncludes (resp, includes, relations, app) {
   })
 
   if (embedded.length) {
-    resp.included = _.flattenDeep(embedded)
+    // This array may contain duplicate models if the same item is referenced multiple times in 'data'
+    var duplicate = _.flattenDeep(embedded)
+    // So begin with an empty array that will only contain unique items
+    var unique = []
+    // Iterate through each item in the first array
+    duplicate.forEach(function (d) {
+      // Count the number of items in the unique array with matching 'type' AND 'id'
+      // Since we're adhering to the JSONAPI spec, both 'type' and 'id' can assumed to be present
+      // Both 'type' and 'id' are needed for comparison because we could theoretically have objects of different
+      // types who happen to have the same 'id', and those would not be considered duplicates
+      var count = unique.filter(function (u) {
+        return (u.type === d.type) && (u.id === d.id)
+      }).length
+      // If there are no matching entries, then add the item to the unique array
+      if (count === 0) {
+        unique.push(d)
+      }
+    })
+    resp.included = unique
   }
 }
 

test/hasManyRelationships.test.js

@@ -113,4 +113,29 @@ describe('loopback json api hasMany relationships', function () {
         })
     })
   })
+
+  describe('Duplicate models in `includes`', function () {
+    beforeEach(function () {
+      const Foo = ds.createModel('foo', {title: String})
+      app.model(Foo)
+      const Bar = ds.createModel('bar', {title: String})
+      app.model(Bar)
+      Foo.hasMany(Bar)
+      Foo.belongsTo(Bar)
+
+      return Promise.all([
+        Foo.create({title: 'one', barId: 1}),
+        Bar.create({title: 'one', barId: 1, fooId: 1})
+      ])
+    })
+
+    it('should not occur', function () {
+      return request(app).get('/foos/1/?include=bars,bar')
+        .expect(200)
+        .then(function (res) {
+          expect(res.body.included.length).to.equal(1,
+            'Should be exactly 1 item in included array')
+        })
+    })
+  })
 })