unionType $lookup with $unionWith

graphql/schema.graphql

 interface Glyph {
-  id: ID!
+  _id: ID!
 }
 input StringMatchInput {
   _eq: String
@@ -23,10 +23,10 @@ input KnowsObjectQueryInput {
 input KnowsQueryInput {
   _and: [KnowsQueryInput!]
   _or: [KnowsQueryInput!]
-  id: [ID!]
+  _id: [ID!]
 }
 type Knows implements Glyph {
-  id: ID!
+  _id: ID!
   _subj(query: KnowsSubjectQueryInput, page: PageInput): [Knower!]!
   _obj(query: KnowsObjectQueryInput, page: PageInput): [Knowable!]!
 }
@@ -44,10 +44,10 @@ input FollowSubjectQueryInput {
 input FollowsQueryInput {
   _and: [FollowsQueryInput!]
   _or: [FollowsQueryInput!]
-  id: [ID!]
+  _id: [ID!]
 }
 type Follows implements Glyph {
-  id: ID!
+  _id: ID!
   _subj(query: FollowSubjectQueryInput, page: PageInput): [Follower!]!
   _obj(query: FollowObjectQueryInput, page: PageInput): [Followable!]!
 }
@@ -56,7 +56,7 @@ type Follows implements Glyph {
 input UserQueryInput {
   _and: [UserQueryInput!]
   _or: [UserQueryInput!]
-  id: [ID!]
+  _id: [ID!]
   username: StringMatchInput
 }
 
@@ -68,7 +68,7 @@ input UserRelationQueryInput {
 union UserRelation = Knows | Follows
 
 type User implements Glyph {
-  id: ID!
+  _id: ID!
   _rel(query: UserRelationQueryInput, page: PageInput): [UserRelation!]!
   username: String!
 }

src/gql-graph/mongo/buildMongoPipeline.ts

@@ -2,47 +2,62 @@ import { DocumentSelection } from '../types'
 import { isUnionLookupField } from '../buildDocumentSelection'
 export const buildMongoPipeline = (docS: DocumentSelection, notTop?: boolean) => {
   const lookups = [] as any[]
-  const project = {} as Record<string, string>
+  const project = { __typename: true } as Record<string, any>
 
-  Object.entries(docS).forEach(([alias, field]) => {
+  Object.entries(docS).forEach(([_alias, field]) => {
     if (isUnionLookupField(field)) {
-      const $mainMatchUnionMatch = { $or: [] as any[] }
-      const $mainMatch = { $and: [$mainMatchUnionMatch] }
-      const pipeline = [{ $match: $mainMatch }] as any[]
-      const $lookup = {
+      const unionLookupPipeline = [] as any[]
+      let _let: any = undefined
+      const mainLookup = {
         as: field.alias,
-        let: {} as Record<string, string>,
         from: 'Graph',
-        pipeline,
-      }
-
+        pipeline: [],
+      } as any
       if (field.traverseRelation) {
         if (field.traverseRelation === '_rel') {
-          $lookup.let.nodeId = '$_id'
+          _let = { nodeId: '$_id' }
 
           notTop &&
-            $mainMatch.$and.push({
-              // $expr: { $eq: [`$${field.traverseRelation}`, '$$nodeId'] },
-              $expr: { $eq: [`$_subj`, '$$nodeId'] },
-            } as any)
+            unionLookupPipeline.push({
+              $match: {
+                // $expr: { $eq: [`$${field.traverseRelation}`, '$$nodeId'] },
+                $expr: { $eq: [`$_subj`, '$$nodeId'] },
+              },
+            })
         } else {
-          $lookup.let.edgeSide = `$${field.traverseRelation}` //=== '_obj' ? '$_subj' : '$_obj'
-          notTop && $mainMatch.$and.push({ $expr: { $eq: [`$_id`, '$$edgeSide'] } } as any)
+          _let = { edgeSide: `$${field.traverseRelation}` } //=== '_obj' ? '$_subj' : '$_obj'
+          notTop && unionLookupPipeline.push({ $match: { $expr: { $eq: [`$_id`, '$$edgeSide'] } } })
         }
       }
 
-      field.lookups.forEach((fieldLookup) => {
+      field.lookups.forEach((fieldLookup, index) => {
         const $match = { $and: [{ __typename: fieldLookup.__typename }] as any[] }
-        $mainMatchUnionMatch.$or.push($match)
         fieldLookup.match && $match.$and.push(fieldLookup.match)
-        pipeline.push(...buildMongoPipeline(fieldLookup.select, true))
-      })
-      project[field.alias] = `$${field.alias}`
-      lookups.push({
-        $lookup,
+
+        if (!index) {
+          mainLookup.pipeline = [
+            ...unionLookupPipeline,
+            { $match },
+            ...buildMongoPipeline(fieldLookup.select, true),
+          ]
+          _let && (mainLookup.let = _let)
+          lookups.push({ $lookup: mainLookup })
+        } else {
+          mainLookup.pipeline.push({
+            $unionWith: {
+              coll: 'Graph',
+              pipeline: [
+                ...unionLookupPipeline,
+                { $match },
+                ...buildMongoPipeline(fieldLookup.select, true) /* [0].$lookup.pipeline */,
+              ],
+            },
+          })
+        }
       })
+      project[field.alias] = true
     } else {
-      project[alias] = `$${field.fieldName}`
+      project[field.alias] = field.alias === field.fieldName ? true : `$${field.fieldName}`
     }
   })
   if (notTop) {

src/gql-graph/mongo/mappers.ts

 import { ObjectID } from 'mongodb'
 import { GqlNode, GqlRelation, ShallowEntity, ShallowRelation } from '../types'
-export type MongoNode<T extends GqlNode> = Omit<T, 'id' | '_rel'> & { _id: ObjectID }
-export type MongoRelation<T extends GqlRelation> = Omit<T, 'id' | '_subj' | '_obj'> & {
+export type MongoNode<T extends GqlNode> = Omit<T, '_id' | '_rel'> & { _id: ObjectID }
+export type MongoRelation<T extends GqlRelation> = Omit<T, '_id' | '_subj' | '_obj'> & {
   _id: ObjectID
   _obj: ObjectID
   _subj: ObjectID
 }
 
 export const toMongoNode = <Node extends GqlNode>(
-  gql_node: ShallowEntity<Node> | Omit<ShallowEntity<Node>, 'id'>
+  gql_node: ShallowEntity<Node> | Omit<ShallowEntity<Node>, '_id'>
 ): MongoNode<Node> => {
-  const _id = 'id' in gql_node ? new ObjectID(gql_node.id) : new ObjectID()
+  const _id = '_id' in gql_node ? new ObjectID(gql_node._id) : new ObjectID()
 
   const mongo_node = Object.entries(gql_node).reduce(
     (constructing_mongo_node, [key, val]) => {
-      if (['id', '_rel'].includes(key)) {
+      if (['_id', '_rel'].includes(key)) {
         return constructing_mongo_node
       }
       return {
@@ -31,15 +31,15 @@ export const toMongoNode = <Node extends GqlNode>(
 }
 
 export const toMongoRelation = <Rel extends GqlRelation>(
-  gql_node: ShallowRelation<Rel> | Omit<ShallowRelation<Rel>, 'id'>,
+  gql_node: ShallowRelation<Rel> | Omit<ShallowRelation<Rel>, '_id'>,
   obj: ObjectID | string,
   subj: ObjectID | string
 ): MongoRelation<Rel> => {
-  const _id = 'id' in gql_node ? new ObjectID(gql_node.id) : new ObjectID()
+  const _id = '_id' in gql_node ? new ObjectID(gql_node._id) : new ObjectID()
 
   const mongo_rel = Object.entries(gql_node).reduce(
     (constructing_mongo_rel, [key, val]) => {
-      if (['id'].includes(key)) {
+      if (['_id'].includes(key)) {
         return constructing_mongo_rel
       }
       return {

src/gql-graph/types.d.ts

@@ -3,7 +3,7 @@ import { ObjectID } from 'mongodb'
 export type ShallowEntity<T> = Omit<T, '_rel'>
 export type ShallowRelation<T> = Omit<T, '_obj' | '_subj'>
 
-export type GqlType = { id: string; __typename: string }
+export type GqlType = { _id: string; __typename: string }
 export type GqlNode = GqlType & { _rel: any[] }
 export type GqlRelation = GqlType & { _obj: any; _subj: any }
 

src/gql/graphql.schema.json

@@ -14,7 +14,7 @@
         "description": null,
         "fields": [
           {
-            "name": "id",
+            "name": "_id",
             "description": null,
             "args": [],
             "type": {
@@ -270,7 +270,7 @@
             "defaultValue": null
           },
           {
-            "name": "id",
+            "name": "_id",
             "description": null,
             "type": {
               "kind": "LIST",
@@ -298,7 +298,7 @@
         "description": null,
         "fields": [
           {
-            "name": "id",
+            "name": "_id",
             "description": null,
             "args": [],
             "type": {
@@ -532,7 +532,7 @@
             "defaultValue": null
           },
           {
-            "name": "id",
+            "name": "_id",
             "description": null,
             "type": {
               "kind": "LIST",
@@ -560,7 +560,7 @@
         "description": null,
         "fields": [
           {
-            "name": "id",
+            "name": "_id",
             "description": null,
             "args": [],
             "type": {
@@ -720,7 +720,7 @@
             "defaultValue": null
           },
           {
-            "name": "id",
+            "name": "_id",
             "description": null,
             "type": {
               "kind": "LIST",
@@ -810,7 +810,7 @@
         "description": null,
         "fields": [
           {
-            "name": "id",
+            "name": "_id",
             "description": null,
             "args": [],
             "type": {

src/gql/resolvers/mutation/createFollows.ts

@@ -13,5 +13,5 @@ export const createFollows: MutationResolvers['createFollows'] = async (_parent,
   )
   const c = await collection<Follows>()
   await c.insertOne(newFollows)
-  return null //{ ...newFollows, id: newFollows._id.toHexString(), _obj: [], _subj: [] }
+  return null //{ ...newFollows, _id: newFollows._id.toHexString(), _obj: [], _subj: [] }
 }

src/gql/resolvers/mutation/createKnows.ts

@@ -13,5 +13,5 @@ export const createKnows: MutationResolvers['createKnows'] = async (_parent, arg
   )
   const c = await collection<Knows>()
   await c.insertOne(newKnows)
-  return null //{ ...newKnows, id: newKnows._id.toHexString(), _obj: [], _subj: [] }
+  return null //{ ...newKnows, _id: newKnows._id.toHexString(), _obj: [], _subj: [] }
 }

src/gql/resolvers/mutation/createUser.ts

@@ -12,5 +12,5 @@ export const createUser: MutationResolvers['createUser'] = async (
   })
   const c = await collection<User>()
   await c.insertOne(newUser)
-  return null //{ ...newUser, id: newUser._id.toHexString(), _rel: [] }
+  return null //{ ...newUser, _id: newUser._id.toHexString(), _rel: [] }
 }

src/gql/resolvers/types/index.ts

 import { defaultGraphFieldResolver } from '../../../gql-graph/defaultGraphFieldResolver'
 export const Types = {
   User: {
-    id: defaultGraphFieldResolver(),
+    _id: defaultGraphFieldResolver(),
     _rel: defaultGraphFieldResolver(),
     username: defaultGraphFieldResolver(),
   },
   Knows: {
-    id: defaultGraphFieldResolver(),
+    _id: defaultGraphFieldResolver(),
     _subj: defaultGraphFieldResolver(),
     _obj: defaultGraphFieldResolver(),
   },
   Follows: {
-    id: defaultGraphFieldResolver(),
+    _id: defaultGraphFieldResolver(),
     _subj: defaultGraphFieldResolver(),
     _obj: defaultGraphFieldResolver(),
   },

src/gql/shallowTypes/Follows.ts

@@ -3,5 +3,5 @@ import * as Types from '../types'
 
 export const Follows = (tag: string): ShallowRelation<Types.Follows> => ({
   __typename: 'Follows',
-  id: `id[${tag}]`,
+  _id: `_id[${tag}]`,
 })

src/gql/shallowTypes/Knows.ts

@@ -3,5 +3,5 @@ import * as Types from '../types'
 
 export const Knows = (tag: string): ShallowRelation<Types.Knows> => ({
   __typename: 'Knows',
-  id: `id[${tag}]`,
+  _id: `_id[${tag}]`,
 })

src/gql/shallowTypes/User.ts

@@ -2,6 +2,6 @@ import { ShallowEntity } from '../../gql-graph/types'
 import * as Types from '../types'
 export const User = (tag: string): ShallowEntity<Types.User> => ({
   __typename: 'User',
-  id: `id[${tag}]`,
+  _id: `_id[${tag}]`,
   username: `username[${tag}]`,
 })

src/gql/types.ts

@@ -14,7 +14,7 @@ export type Scalars = {
 };
 
 export type Glyph = {
-  id: Scalars['ID'];
+  _id: Scalars['ID'];
 };
 
 export type StringMatchInput = {
@@ -43,12 +43,12 @@ export type KnowsObjectQueryInput = {
 export type KnowsQueryInput = {
   _and: Maybe<Array<KnowsQueryInput>>;
   _or: Maybe<Array<KnowsQueryInput>>;
-  id: Maybe<Array<Scalars['ID']>>;
+  _id: Maybe<Array<Scalars['ID']>>;
 };
 
 export type Knows = Glyph & {
   __typename: 'Knows';
-  id: Scalars['ID'];
+  _id: Scalars['ID'];
   _subj: Array<Knower>;
   _obj: Array<Knowable>;
 };
@@ -80,12 +80,12 @@ export type FollowSubjectQueryInput = {
 export type FollowsQueryInput = {
   _and: Maybe<Array<FollowsQueryInput>>;
   _or: Maybe<Array<FollowsQueryInput>>;
-  id: Maybe<Array<Scalars['ID']>>;
+  _id: Maybe<Array<Scalars['ID']>>;
 };
 
 export type Follows = Glyph & {
   __typename: 'Follows';
-  id: Scalars['ID'];
+  _id: Scalars['ID'];
   _subj: Array<Follower>;
   _obj: Array<Followable>;
 };
@@ -105,7 +105,7 @@ export type Follows_ObjArgs = {
 export type UserQueryInput = {
   _and: Maybe<Array<UserQueryInput>>;
   _or: Maybe<Array<UserQueryInput>>;
-  id: Maybe<Array<Scalars['ID']>>;
+  _id: Maybe<Array<Scalars['ID']>>;
   username: Maybe<StringMatchInput>;
 };
 
@@ -118,7 +118,7 @@ export type UserRelation = Knows | Follows;
 
 export type User = Glyph & {
   __typename: 'User';
-  id: Scalars['ID'];
+  _id: Scalars['ID'];
   _rel: Array<UserRelation>;
   username: Scalars['String'];
 };
@@ -331,7 +331,7 @@ export type ResolversParentTypes = {
 
 export type GlyphResolvers<ContextType = Context, ParentType extends ResolversParentTypes['Glyph'] = ResolversParentTypes['Glyph']> = {
   __resolveType: TypeResolveFn<'Knows' | 'Follows' | 'User', ParentType, ContextType>;
-  id: Resolver<ResolversTypes['ID'], ParentType, ContextType>;
+  _id: Resolver<ResolversTypes['ID'], ParentType, ContextType>;
 };
 
 export type KnowerResolvers<ContextType = Context, ParentType extends ResolversParentTypes['Knower'] = ResolversParentTypes['Knower']> = {
@@ -343,7 +343,7 @@ export type KnowableResolvers<ContextType = Context, ParentType extends Resolver
 };
 
 export type KnowsResolvers<ContextType = Context, ParentType extends ResolversParentTypes['Knows'] = ResolversParentTypes['Knows']> = {
-  id: Resolver<ResolversTypes['ID'], ParentType, ContextType>;
+  _id: Resolver<ResolversTypes['ID'], ParentType, ContextType>;
   _subj: Resolver<Array<ResolversTypes['Knower']>, ParentType, ContextType, RequireFields<Knows_SubjArgs, never>>;
   _obj: Resolver<Array<ResolversTypes['Knowable']>, ParentType, ContextType, RequireFields<Knows_ObjArgs, never>>;
   __isTypeOf?: IsTypeOfResolverFn<ParentType, ContextType>;
@@ -358,7 +358,7 @@ export type FollowableResolvers<ContextType = Context, ParentType extends Resolv
 };
 
 export type FollowsResolvers<ContextType = Context, ParentType extends ResolversParentTypes['Follows'] = ResolversParentTypes['Follows']> = {
-  id: Resolver<ResolversTypes['ID'], ParentType, ContextType>;
+  _id: Resolver<ResolversTypes['ID'], ParentType, ContextType>;
   _subj: Resolver<Array<ResolversTypes['Follower']>, ParentType, ContextType, RequireFields<Follows_SubjArgs, never>>;
   _obj: Resolver<Array<ResolversTypes['Followable']>, ParentType, ContextType, RequireFields<Follows_ObjArgs, never>>;
   __isTypeOf?: IsTypeOfResolverFn<ParentType, ContextType>;
@@ -369,7 +369,7 @@ export type UserRelationResolvers<ContextType = Context, ParentType extends Reso
 };
 
 export type UserResolvers<ContextType = Context, ParentType extends ResolversParentTypes['User'] = ResolversParentTypes['User']> = {
-  id: Resolver<ResolversTypes['ID'], ParentType, ContextType>;
+  _id: Resolver<ResolversTypes['ID'], ParentType, ContextType>;
   _rel: Resolver<Array<ResolversTypes['UserRelation']>, ParentType, ContextType, RequireFields<User_RelArgs, never>>;
   username: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   __isTypeOf?: IsTypeOfResolverFn<ParentType, ContextType>;

src/http/index.ts

@@ -28,9 +28,10 @@ const executor: GraphQLServerOptions['executor'] = async (requestContext) => {
   console.dir({ 'executor documentSelection': documentSelection }, { depth: 15 })
   if (documentSelection) {
     const pipeline = buildMongoPipeline(documentSelection)
-    console.log('executor pipeline', JSON.stringify(pipeline, null, 4))
-    const c = await collection<any>()
-    return { data: await c.aggregate(pipeline).toArray() }
+    console.log('executor pipeline', JSON.stringify(pipeline, null, 2))
+    const coll = await collection<any>()
+    const data = await coll.aggregate(pipeline).toArray()
+    return { data }
   }
   return Promise.resolve(res)
 }