Add a fix to the calculations

primer · Nov 14, 2023 · ecb0717 · ecb0717
1 parent c18ae86
commit ecb0717
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Showing 2 changed files with 3 additions and 2 deletions.
diff --git a/src/__tests__/anchored-position.test.ts b/src/__tests__/anchored-position.test.ts
@@ -378,7 +378,7 @@ describe('getAnchoredPosition', () => {
     // Not really sure what to expect here.
     expect(anchorSide).toEqual('outside-right')
     expect(anchorAlign).toEqual('start')
-    expect(top).toEqual(-28) // should be 16 which is the top start of the anchor element. Negative value is wrong.
+    expect(top).toEqual(0)
     expect(left).toEqual(52)
   })
 })
diff --git a/src/anchored-position.ts b/src/anchored-position.ts
@@ -370,7 +370,8 @@ function pureCalculateAnchoredPosition(
     // likely to be able to scroll.
     if (alternateOrder && positionAttempt < alternateOrder.length) {
       if (pos.top + floatingRect.height > viewportRect.height + relativeViewportRect.top) {
-        pos.top = viewportRect.height + relativeViewportRect.top - floatingRect.height
+        // This prevents top from being a negative value
+        pos.top = Math.max(viewportRect.height + relativeViewportRect.top - floatingRect.height, 0)
       }
     }
   }