Created Projection Dotify function

Author: natac13

src/__tests__/github_issues/271-test.ts

@@ -77,10 +77,25 @@ describe('nested projection - issue #271', () => {
       contextValue: {},
     });
     console.log(JSON.stringify(result));
-    // expect(BookModel.find).toHaveBeenCalledTimes(1);
-    // expect(BookModel.find).toHaveBeenCalledWith(
-    //   {},
-    //   { limit: 1000, projection: { title: true, pageCount: true, 'author.name': true } }
-    // );
+  });
+
+  it('Handles a Fragment', async () => {
+    const result = await graphql.graphql({
+      schema,
+      source: `
+        fragment Auth on Author {
+          name
+        }
+
+        query {
+          booksMany {
+            title
+            pageCount
+            author { ...Auth }
+          }
+        }`,
+      contextValue: {},
+    });
+    console.log(JSON.stringify(result));
   });
 });

src/resolvers/helpers/dotify.ts

@@ -0,0 +1,26 @@
+const dotify = (object: Record<string, any>) => {
+  const res: Record<string, number> = {};
+
+  function recurse(obj: Record<string, any>, current?: string) {
+    const objKeys = Object.keys(obj);
+
+    objKeys.forEach((key: string) => {
+      const value = obj[key];
+
+      const newKey = current ? `${current}.${key}` : key;
+      if (value && (value.$meta || value.$slice || value.$elemMatch)) {
+        // pass MongoDB projection operators https://docs.mongodb.com/v3.2/reference/operator/projection/meta/
+        res[newKey] = 1;
+      } else if (value && typeof value === 'object' && Object.keys(value).length > 0) {
+        recurse(value, newKey);
+      } else {
+        res[newKey] = 1;
+      }
+    });
+  }
+
+  recurse(object);
+  return res;
+};
+
+export default dotify;

src/resolvers/helpers/projection.ts

@@ -1,5 +1,6 @@
 import type { ExtendedResolveParams } from '../index';
 import type { AliasesMap } from './aliases';
+import dotify from './dotify';
 
 export function projectionHelper(
   resolveParams: ExtendedResolveParams,
@@ -11,17 +12,7 @@ export function projectionHelper(
     if (projection['*']) {
       return;
     }
-    const flatProjection: Record<string, any> = {};
-    Object.keys(projection).forEach((key) => {
-      const val = projection[key];
-      if (val && (val.$meta || val.$slice || val.$elemMatch)) {
-        // pass MongoDB projection operators https://docs.mongodb.com/v3.2/reference/operator/projection/meta/
-        flatProjection[key] = val;
-      } else {
-        // if not projection operator, then flatten projection
-        flatProjection[key] = !!val;
-      }
-    });
+    const flatProjection: Record<string, any> = dotify(projection);
 
     if (aliases) {
       Object.keys(flatProjection).forEach((k) => {