fix: normalize yoffset

table/table.go

@@ -350,14 +350,17 @@ func (m *Model) SetCursor(n int) {
 // It can not go above the first row.
 func (m *Model) MoveUp(n int) {
 	m.cursor = clamp(m.cursor-n, 0, len(m.rows)-1)
+
+	offset := m.viewport.YOffset()
 	switch {
 	case m.start == 0:
-		m.viewport.SetYOffset(clamp(m.viewport.YOffset, 0, m.cursor))
+		offset = clamp(offset, 0, m.cursor)
 	case m.start < m.viewport.Height():
-		m.viewport.YOffset = (clamp(clamp(m.viewport.YOffset+n, 0, m.cursor), 0, m.viewport.Height()))
-	case m.viewport.YOffset >= 1:
-		m.viewport.YOffset = clamp(m.viewport.YOffset+n, 1, m.viewport.Height())
+		offset = clamp(clamp(offset+n, 0, m.cursor), 0, m.viewport.Height())
+	case offset >= 1:
+		offset = clamp(offset+n, 1, m.viewport.Height())
 	}
+	m.viewport.SetYOffset(offset)
 	m.UpdateViewport()
 }
 
@@ -367,15 +370,17 @@ func (m *Model) MoveDown(n int) {
 	m.cursor = clamp(m.cursor+n, 0, len(m.rows)-1)
 	m.UpdateViewport()
 
+	offset := m.viewport.YOffset()
 	switch {
-	case m.end == len(m.rows) && m.viewport.YOffset > 0:
-		m.viewport.SetYOffset(clamp(m.viewport.YOffset-n, 1, m.viewport.Height()))
-	case m.cursor > (m.end-m.start)/2 && m.viewport.YOffset > 0:
-		m.viewport.SetYOffset(clamp(m.viewport.YOffset-n, 1, m.cursor))
-	case m.viewport.YOffset > 1:
-	case m.cursor > m.viewport.YOffset+m.viewport.Height()-1:
-		m.viewport.SetYOffset(clamp(m.viewport.YOffset+1, 0, 1))
+	case m.end == len(m.rows) && offset > 0:
+		offset = clamp(offset-n, 1, m.viewport.Height())
+	case m.cursor > (m.end-m.start)/2 && offset > 0:
+		offset = clamp(offset-n, 1, m.cursor)
+	case offset > 1:
+	case m.cursor > offset+m.viewport.Height()-1:
+		offset = clamp(offset+1, 0, 1)
 	}
+	m.viewport.SetYOffset(offset)
 }
 
 // GotoTop moves the selection to the first row.