refactor(grid): use an array to store nearby entries

imports/grid/shared.lua

@@ -32,7 +32,7 @@ local xDelta = (mapMaxX - mapMinX) / 34
 local yDelta = (mapMaxY - mapMinY) / 50
 local grid = {}
 local lastCell = {}
-local lastNearbyEntries = {}
+local gridCache = {}
 local entrySet = {}
 
 lib.grid = {}
@@ -82,18 +82,18 @@ end
 
 ---@param point vector
 ---@param filter? fun(entry: GridEntry): boolean
----@return GridEntry[]
+---@return Array<GridEntry>
 function lib.grid.getNearbyEntries(point, filter)
     local minX, maxX, minY, maxY = getGridDimensions(point, xDelta, yDelta)
 
-    if lastNearbyEntries.minX == minX and
-        lastNearbyEntries.maxX == maxX and
-        lastNearbyEntries.minY == minY and
-        lastNearbyEntries.maxY == maxY then
-        return lastNearbyEntries.entries
+    if gridCache.minX == minX and
+        gridCache.maxX == maxX and
+        gridCache.minY == minY and
+        gridCache.maxY == maxY then
+        return gridCache.entries
     end
 
-    local entries = {}
+    local entries = lib.array:new()
     local n = 0
 
     table.wipe(entrySet)
@@ -118,11 +118,11 @@ function lib.grid.getNearbyEntries(point, filter)
         end
     end
 
-    lastNearbyEntries.minX = minX
-    lastNearbyEntries.maxX = maxX
-    lastNearbyEntries.minY = minY
-    lastNearbyEntries.maxY = maxY
-    lastNearbyEntries.entries = entries
+    gridCache.minX = minX
+    gridCache.maxX = maxX
+    gridCache.minY = minY
+    gridCache.maxY = maxY
+    gridCache.entries = entries
 
     return entries
 end
@@ -145,7 +145,7 @@ function lib.grid.addEntry(entry)
 
         grid[y] = row
 
-        table.wipe(lastNearbyEntries)
+        table.wipe(gridCache)
     end
 end
 
@@ -184,7 +184,7 @@ function lib.grid.removeEntry(entry)
         ::continue::
     end
 
-    table.wipe(lastNearbyEntries)
+    table.wipe(gridCache)
 
     return success
 end