From ba0050a637824477f7666ebf0564dafd94976589 Mon Sep 17 00:00:00 2001
From: GatsbyJS Bot <mathews.kyle+gatsbybot@gmail.com>
Date: Fri, 16 Jul 2021 04:06:56 -0400
Subject: [PATCH] fix(gatsby): correct hasNextPage pagination info when
 resultOffset is provided (#32319) (#32386)

(cherry picked from commit 9f8a580287ec3a4bf9696237e7e8ac49e2fc001c)

Co-authored-by: Angelo Ashmore <angeloashmore@users.noreply.github.com>
---
 .../gatsby/src/schema/__tests__/pagination.js | 21 ++++++++++++++++++-
 packages/gatsby/src/schema/resolvers.ts       | 19 ++++++++++++++++-
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/packages/gatsby/src/schema/__tests__/pagination.js b/packages/gatsby/src/schema/__tests__/pagination.js
index 8db457266f9ba..4518c0b520457 100644
--- a/packages/gatsby/src/schema/__tests__/pagination.js
+++ b/packages/gatsby/src/schema/__tests__/pagination.js
@@ -154,7 +154,7 @@ describe(`Paginate query results`, () => {
   })
 
   it(`returns correct pagination info with skip, limit and resultOffset`, async () => {
-    const args = { skip: 2, limit: 2, resultOffset: 1 }
+    const args = { skip: 1, limit: 2, resultOffset: 1 }
     const { pageInfo, totalCount } = paginate(results, args)
     expect(typeof totalCount).toBe(`function`)
     expect(await totalCount()).toBe(4)
@@ -168,6 +168,25 @@ describe(`Paginate query results`, () => {
       perPage: 2,
       totalCount: expect.toBeFunction(),
     })
+    expect(await pageInfo.pageCount()).toEqual(3)
+    expect(await pageInfo.totalCount()).toEqual(4)
+  })
+
+  it(`returns correct pagination info with skip, limit and resultOffset on the last page`, async () => {
+    const args = { skip: 2, limit: 2, resultOffset: 1 }
+    const { pageInfo, totalCount } = paginate(results, args)
+    expect(typeof totalCount).toBe(`function`)
+    expect(await totalCount()).toBe(4)
+
+    expect(pageInfo).toEqual({
+      currentPage: 2,
+      hasNextPage: false,
+      hasPreviousPage: true,
+      itemCount: 2,
+      pageCount: expect.toBeFunction(),
+      perPage: 2,
+      totalCount: expect.toBeFunction(),
+    })
     expect(await pageInfo.pageCount()).toEqual(2)
     expect(await pageInfo.totalCount()).toEqual(4)
   })
diff --git a/packages/gatsby/src/schema/resolvers.ts b/packages/gatsby/src/schema/resolvers.ts
index bd452c35ab894..b89e47d06f531 100644
--- a/packages/gatsby/src/schema/resolvers.ts
+++ b/packages/gatsby/src/schema/resolvers.ts
@@ -288,7 +288,24 @@ export function paginate(
   }
   const currentPage = limit ? Math.ceil(skip / limit) + 1 : skip ? 2 : 1
   const hasPreviousPage = currentPage > 1
-  const hasNextPage = limit ? allItems.length - start > limit : false
+
+  let hasNextPage = false
+  // If limit is not defined, there will never be a next page.
+  if (limit) {
+    if (resultOffset > 0) {
+      // If resultOffset is greater than 0, we need to test if `allItems` contains
+      // items that should be skipped.
+      //
+      // This is represented if the `start` index offset is 0 or less. A start
+      // greater than 0 means `allItems` contains extra items that would come
+      // before the skipped items.
+      hasNextPage = start < 1
+    } else {
+      // If the resultOffset is 0, we can test if `allItems` contains more items
+      // than the limit after removing the skipped items.
+      hasNextPage = allItems.length - start > limit
+    }
+  }
 
   return {
     totalCount,