Add keepParentField support

README.md

@@ -291,6 +291,32 @@ projection = {
 */
 ```
 
+Projections also accepts keepParentField option, which should return the parents included in the object not only the leaves.
+
+```javascript
+const projection = fieldsProjection(info, {
+    path: 'users',
+    keepParentField: true,
+});
+/*
+RESULT:
+projection = {
+  'edges': 1,                 // parent node
+  'edges.node': 1,            // parent node
+  'pageInfo': 1,              // parent node
+  'pageInfo.startCursor': 1,
+  'pageInfo.endCursor': 1,
+  'pageInfo.hasNextPage': 1,
+  'edges.node.id': 1,
+  'edges.node.firstName': 1,
+  'edges.node.lastName': 1,
+  'edges.node.phoneNumber': 1,
+  'edges.node.email': 1,
+  'edges.node.address': 1,
+}
+*/
+```
+
 Projections also accepts transform option, which should be a mapping object
 between projections paths:
 

index.ts

@@ -74,6 +74,12 @@ export interface FieldsListOptions {
      */
     withDirectives?: boolean;
 
+    /**
+     * Flag which turns on/off whether to return the parent fields or not
+     * @type {boolean}
+     */
+    keepParentField?: boolean;
+
     /**
      * Fields skip rule patterns. Usually used to ignore part of request field
      * subtree. For example if query looks like:
@@ -547,11 +553,14 @@ export function fieldsProjection(
     while (stack.length) {
         for (const j of Object.keys(stack[0].tree)) {
             if (stack[0].tree[j]) {
+                const nodeDottedName = toDotNotation(stack[0].node, j);
                 stack.push({
-                    node: toDotNotation(stack[0].node, j),
+                    node: nodeDottedName,
                     tree: stack[0].tree[j],
                 });
 
+                if (options?.keepParentField) map[nodeDottedName] = 1;
+
                 continue;
             }
 

test/index.ts

@@ -138,6 +138,90 @@ describe('module "graphql-fields-list"', () => {
             });
         });
 
+
+        it('should extract proper fields if keepParentField is specified', () => {
+            expect(
+                fieldsProjection(info, { keepParentField: true })
+            ).deep.equals({
+                users: 1,
+                "users.edges": 1,
+                "users.edges.node": 1,
+                "users.pageInfo": 1,
+                "users.pageInfo.startCursor": 1,
+                "users.pageInfo.endCursor": 1,
+                "users.pageInfo.hasNextPage": 1,
+                "users.edges.node.id": 1,
+                "users.edges.node.firstName": 1,
+                "users.edges.node.lastName": 1,
+                "users.edges.node.phoneNumber": 1,
+                "users.edges.node.email": 1,
+                "users.edges.node.address": 1,
+            });
+            expect(
+                fieldsProjection(info, {
+                    path: "users",
+                    keepParentField: true,
+                })
+            ).deep.equals({
+                edges: 1,
+                "edges.node": 1,
+                pageInfo: 1,
+                "pageInfo.startCursor": 1,
+                "pageInfo.endCursor": 1,
+                "pageInfo.hasNextPage": 1,
+                "edges.node.id": 1,
+                "edges.node.firstName": 1,
+                "edges.node.lastName": 1,
+                "edges.node.phoneNumber": 1,
+                "edges.node.email": 1,
+                "edges.node.address": 1,
+            });
+            expect(
+                fieldsProjection(info, {
+                    skip: ["users.pageInfo"],
+                    path: "users",
+                    keepParentField: true,
+                })
+            ).deep.equals({
+                edges: 1,
+                "edges.node": 1,
+                "edges.node.id": 1,
+                "edges.node.firstName": 1,
+                "edges.node.lastName": 1,
+                "edges.node.phoneNumber": 1,
+                "edges.node.email": 1,
+                "edges.node.address": 1,
+            });
+            expect(fieldsProjection(info, {
+                path: 'users.edges.node',
+                keepParentField: true,
+            })).deep.equals({
+                'id': 1,
+                'firstName': 1,
+                'lastName': 1,
+                'phoneNumber': 1,
+                'email': 1,
+                'address': 1,
+            });
+            expect(fieldsProjection(info, {
+                path: 'users.edges',
+                keepParentField: true,
+                transform: {
+                    'node.id': 'node._id',
+                    'node.firstName': 'node.given_name',
+                    'node.lastName': 'node.family_name',
+                },
+            })).deep.equals({
+                "node": 1,
+                'node._id': 1,
+                'node.given_name': 1,
+                'node.family_name': 1,
+                'node.phoneNumber': 1,
+                'node.email': 1,
+                'node.address': 1,
+            });
+        });
+
         it('should properly transform field names', () => {
             expect(fieldsProjection(info, {
                 path: 'users.edges.node',