feat(fragment): add fragment support with broken projection

example/app.js

@@ -7,21 +7,21 @@ var schema = getSchema([User]);
 
 mongoose.connect('mongodb://localhost/graphql');
 
-var query = `{
-  user(_id: "559645cd1a38532d14349246") {
+var query = `
+  query GetUser {
+    user(_id: "559645cd1a38532d14349246") {
+      ...UserFragment
+      friends {
+        ...UserFragment
+      }
+    }
+  }
+
+  fragment UserFragment on User {
     name
     age
-    createdAt
-    nums
-    bools
-    strings
-    removed
-    friends {
-      name
-      age
-    }
   }
-}`;
+`;
 
 // query = `{
 //   users(age: 19) {

src/e2e.spec.js

@@ -64,7 +64,7 @@ describe('e2e', () => {
         _schemaConfig: {
           query: {
             name: 'RootQueryType',
-            description: 'Query schema for Graffiti'    
+            description: 'Query schema for Graffiti'
           }
         }
       });
@@ -99,37 +99,73 @@ describe('e2e', () => {
         });
       });
 
-      it('should support inline fragments', function* () {
-        let result = yield graphql(schema, `{
-          user(_id: "${user2._id}") {
-            _id
-            name,
-            ... on User {
+      describe('with fragments', () => {
+        it('should support fragments', function* () {
+          let result = yield graphql(schema, `
+            query GetUser {
+              user(_id: "${user2._id}") {
+                ...UserFragment
+                friends {
+                  ...UserFragment
+                }
+              }
+            }
+
+            fragment UserFragment on User {
+              _id
+              name
               age
             }
-            friends {
+          `);
+
+          expect(result).to.be.eql({
+            data: {
+              user: {
+                _id: user2._id.toString(),
+                name: 'Bar',
+                age: 28,
+                friends: [{
+                  _id: user1._id.toString(),
+                  name: 'Foo',
+                  age: 28
+                }]
+              },
+            }
+          });
+        });
+
+        it('should support inline fragments', function* () {
+          let result = yield graphql(schema, `{
+            user(_id: "${user2._id}") {
               _id
+              name,
               ... on User {
-                name
+                age
+              }
+              friends {
+                _id
+                ... on User {
+                  name
+                },
+                age
+              }
+            }
+          }`);
+
+          expect(result).to.be.eql({
+            data: {
+              user: {
+                _id: user2._id.toString(),
+                name: 'Bar',
+                age: 28,
+                friends: [{
+                  _id: user1._id.toString(),
+                  name: 'Foo',
+                  age: 28
+                }]
               },
-              age
             }
-          }
-        }`);
-
-        expect(result).to.be.eql({
-          data: {
-            user: {
-              _id: user2._id.toString(),
-              name: 'Bar',
-              age: 28,
-              friends: [{
-                _id: user1._id.toString(),
-                name: 'Foo',
-                age: 28
-              }]
-            },
-          }
+          });
         });
       });
     });

src/projection.js

@@ -1,26 +1,47 @@
+import {find} from 'lodash';
+
 /**
  * Generate projection object for mongoose
- * TODO: Handle sub-documents
- * @method get
+ * @method getProjection
  * @param {Object} fieldASTs
- * @return {Project}
+ * @return {Object} projection
  */
-export function getProjection(fieldASTs) {
-  const { selections } = fieldASTs.selectionSet;
+function getProjection(fieldASTs) {
+  const {selections} = fieldASTs.selectionSet;
+
+  /*
+   * FIXME: there is no way currently to get the required fields from "FragmentSpread"
+   * workaround: don't do projection, select all of the fields
+   * related issue: https://github.com/graphql/graphql-js/issues/96
+   */
+  let isFragmentSpread = find(selections, {
+    kind: 'FragmentSpread'
+  });
+
+  if (isFragmentSpread) {
+    return {};
+  }
+
+  // Get projection object
   return selections.reduce((projs, selection) => {
     switch (selection.kind) {
       case 'Field':
         return {
-          ...projs,
-          [selection.name.value]: 1
+          ...projs, [selection.name.value]: 1
         };
+
       case 'InlineFragment':
         return {
           ...projs,
           ...getProjection(selection),
         };
+
       default:
-        throw 'Unsupported query';
+        throw new Error('Unsupported query selection: ' + selection.kind);
     }
   }, {});
 }
+
+export {
+  getProjection
+}

src/projection.spec.js

@@ -26,6 +26,9 @@ describe('utils', () => {
       });
     });
 
+    // TODO: see related method
+    it('should support fragments');
+
     it('should support inline fragments', () => {
       const projectionResult = getProjection({
         selectionSet: {