From e4f45168158a1b2b3717ea1ba45713b27ad2b381 Mon Sep 17 00:00:00 2001
From: Ivan Goncharov <ivan.goncharov.ua@gmail.com>
Date: Mon, 28 Jun 2021 15:37:25 +0300
Subject: [PATCH] arrayConnection: return all elements if cursors are on the
 outside

Fixes #51
---
 .../__tests__/arrayConnection-test.js         | 32 +++++++++++--------
 src/connection/arrayConnection.js             | 20 +++++++++---
 2 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/src/connection/__tests__/arrayConnection-test.js b/src/connection/__tests__/arrayConnection-test.js
index 3cd867f..a20eaed 100644
--- a/src/connection/__tests__/arrayConnection-test.js
+++ b/src/connection/__tests__/arrayConnection-test.js
@@ -2,6 +2,7 @@ import { describe, it } from 'mocha';
 import { expect } from 'chai';
 
 import {
+  offsetToCursor,
   connectionFromArray,
   connectionFromArraySlice,
   connectionFromPromisedArray,
@@ -289,19 +290,24 @@ describe('connectionFromArray()', () => {
     });
 
     it('returns all elements if cursors are on the outside', () => {
-      const c = connectionFromArray(arrayABCDE, {
-        before: 'YXJyYXljb25uZWN0aW9uOjY=' /* offsetToCursor(6) */,
-        after: 'YXJyYXljb25uZWN0aW9uOi0x' /* offsetToCursor(-1) */,
-      });
-      expect(c).to.deep.equal({
-        edges: [edgeA, edgeB, edgeC, edgeD, edgeE],
-        pageInfo: {
-          startCursor: cursorA,
-          endCursor: cursorE,
-          hasPreviousPage: false,
-          hasNextPage: false,
-        },
-      });
+      function expectAllEdges(args: { before?: string, after?: string }) {
+        const c = connectionFromArray(arrayABCDE, args);
+        expect(c).to.deep.equal({
+          edges: [edgeA, edgeB, edgeC, edgeD, edgeE],
+          pageInfo: {
+            startCursor: cursorA,
+            endCursor: cursorE,
+            hasPreviousPage: false,
+            hasNextPage: false,
+          },
+        });
+      }
+
+      expectAllEdges({ before: offsetToCursor(6) });
+      expectAllEdges({ before: offsetToCursor(-1) });
+
+      expectAllEdges({ after: offsetToCursor(-1) });
+      expectAllEdges({ after: offsetToCursor(6) });
     });
 
     it('returns no elements if cursors cross', () => {
diff --git a/src/connection/arrayConnection.js b/src/connection/arrayConnection.js
index 1c8b15c..4f0681e 100644
--- a/src/connection/arrayConnection.js
+++ b/src/connection/arrayConnection.js
@@ -54,11 +54,21 @@ export function connectionFromArraySlice<T>(
   const { after, before, first, last } = args;
   const { sliceStart, arrayLength } = meta;
   const sliceEnd = sliceStart + arraySlice.length;
-  const beforeOffset = getOffsetWithDefault(before, arrayLength);
+
+  let startOffset = Math.max(sliceStart, 0);
+  let endOffset = Math.min(sliceEnd, arrayLength);
+  console.log(startOffset, endOffset);
+
   const afterOffset = getOffsetWithDefault(after, -1);
+  if (0 <= afterOffset && afterOffset < arrayLength) {
+    startOffset = Math.max(startOffset, afterOffset + 1);
+  }
+
+  const beforeOffset = getOffsetWithDefault(before, endOffset);
+  if (0 <= beforeOffset && beforeOffset < arrayLength) {
+    endOffset = Math.min(endOffset, beforeOffset);
+  }
 
-  let startOffset = Math.max(sliceStart - 1, afterOffset, -1) + 1;
-  let endOffset = Math.min(sliceEnd, beforeOffset, arrayLength);
   if (typeof first === 'number') {
     if (first < 0) {
       throw new Error('Argument "first" must be a non-negative integer');
@@ -76,8 +86,8 @@ export function connectionFromArraySlice<T>(
 
   // If supplied slice is too large, trim it down before mapping over it.
   const slice = arraySlice.slice(
-    Math.max(startOffset - sliceStart, 0),
-    arraySlice.length - (sliceEnd - endOffset),
+    startOffset - sliceStart,
+    endOffset - sliceStart,
   );
 
   const edges = slice.map((value, index) => ({