feat: connection total count

Author: calmonr

src/relay/connection.factory.ts

@@ -1,25 +1,26 @@
 import {
-  Connection,
   ConnectionArguments,
   getOffsetWithDefault,
   offsetToCursor
 } from 'graphql-relay'
 import { Repository } from 'typeorm'
 
+import { Connection } from './connection.interface'
+
 export async function connectionFromRepository<T>(
   args: ConnectionArguments,
   repository: Repository<T>
 ): Promise<Connection<T>> {
   const { before, after, first, last } = args
 
-  const total = await repository.count()
+  const totalCount = await repository.count()
 
   // offsets
-  const beforeOffset = getOffsetWithDefault(before, total)
+  const beforeOffset = getOffsetWithDefault(before, totalCount)
   const afterOffset = getOffsetWithDefault(after, -1)
 
   let startOffset = Math.max(-1, afterOffset) + 1
-  let endOffset = Math.min(beforeOffset, total)
+  let endOffset = Math.min(beforeOffset, totalCount)
 
   if (first) {
     endOffset = Math.min(endOffset, startOffset + first)
@@ -44,7 +45,7 @@ export async function connectionFromRepository<T>(
   // page info
   const { length, 0: firstEdge, [length - 1]: lastEdge } = edges
   const lowerBound = after ? afterOffset + 1 : 0
-  const upperBound = before ? Math.min(beforeOffset, total) : total
+  const upperBound = before ? Math.min(beforeOffset, totalCount) : totalCount
 
   const pageInfo = {
     startCursor: firstEdge ? firstEdge.cursor : null,
@@ -55,6 +56,7 @@ export async function connectionFromRepository<T>(
 
   return {
     edges,
-    pageInfo
+    pageInfo,
+    totalCount
   }
 }

src/relay/connection.generic.ts

@@ -1,6 +1,7 @@
-import { Connection, Edge } from 'graphql-relay'
+import { Edge } from 'graphql-relay'
 import { ClassType, Field, ObjectType } from 'type-graphql'
 
+import { Connection } from './connection.interface'
 import { PageInfo } from './page-info.object'
 
 type NodeType<E> = E extends Edge<infer N> ? N : unknown
@@ -18,6 +19,11 @@ export function ConnectionType<E extends Edge<N>, N = NodeType<E>>(
 
     @Field({ description: 'Information to aid in pagination.' })
     readonly pageInfo!: PageInfo
+
+    @Field({
+      description: 'Identifies the total count of items in the connection.'
+    })
+    readonly totalCount!: number
   }
 
   return ConnectionClass

src/relay/connection.interface.ts

@@ -0,0 +1,5 @@
+import { Connection as RelayConnection } from 'graphql-relay'
+
+export interface Connection<T> extends RelayConnection<T> {
+  readonly totalCount: number
+}

src/relay/node.resolver.ts

@@ -38,15 +38,15 @@ export class NodeResolver {
       )
     }
 
-    return repository.findOne(id)
+    return await repository.findOne(id)
   }
 
   // TODO: use dataloader
   @Query(() => Node, {
     nullable: true,
     description: 'Fetches an object given its global ID.'
   })
-  async node(
+  node(
     @Arg('id', () => ID, { description: 'The global ID of the object.' })
     globalId: string,
     @Ctx() context: Context
@@ -58,11 +58,11 @@ export class NodeResolver {
     nullable: 'items',
     description: 'Fetches objects given their global IDs.'
   })
-  async nodes(
+  nodes(
     @Arg('ids', () => [ID], { description: 'The global IDs of the objects.' })
     globalIds: Array<string>,
     @Ctx() context: Context
-  ): Promise<Array<ReturnType<NodeResolver['fetcher']>>> {
+  ): Array<ReturnType<NodeResolver['fetcher']>> {
     return globalIds.map(id => this.fetcher(id, context))
   }
 }

src/relay/page-info.object.ts

@@ -7,23 +7,23 @@ export class PageInfo implements RelayPageInfo {
     nullable: true,
     description: 'When paginating backwards, the cursor to continue.'
   })
-  startCursor?: ConnectionCursor | null
+  readonly startCursor?: ConnectionCursor | null
 
   @Field(() => String, {
     nullable: true,
     description: 'When paginating forwards, the cursor to continue.'
   })
-  endCursor?: ConnectionCursor | null
+  readonly endCursor?: ConnectionCursor | null
 
   @Field(() => Boolean, {
     nullable: true,
     description: 'When paginating backwards, are there more items?'
   })
-  hasPreviousPage?: boolean | null
+  readonly hasPreviousPage?: boolean | null
 
   @Field(() => Boolean, {
     nullable: true,
     description: 'When paginating forwards, are there more items?'
   })
-  hasNextPage?: boolean | null
+  readonly hasNextPage?: boolean | null
 }

tests/functional/relay/connection.test.ts

@@ -22,6 +22,7 @@ query users($before: String, $after: String, $first: Int, $last: Int) {
       hasPreviousPage
       hasNextPage
     }
+    totalCount
   }
 }
 `
@@ -197,4 +198,39 @@ describe('connection', () => {
       })
     })
   })
+
+  describe('total count', () => {
+    test('should return 0', async () => {
+      const result = await graphql({
+        schema,
+        source: USERS_QUERY
+      })
+
+      expect(result.errors).toBeUndefined()
+      expect(result.data).toBeObject()
+      expect(result.data).toMatchObject({
+        users: {
+          totalCount: 0
+        }
+      })
+    })
+
+    test('should return 2', async () => {
+      await repository.save({ name: 'Calmon Ribeiro' })
+      await repository.save({ name: 'Michał Lytek' })
+
+      const result = await graphql({
+        schema,
+        source: USERS_QUERY
+      })
+
+      expect(result.errors).toBeUndefined()
+      expect(result.data).toBeObject()
+      expect(result.data).toMatchObject({
+        users: {
+          totalCount: 2
+        }
+      })
+    })
+  })
 })