⚡ Bolt: 빠른 byte 배열 밀도 확인을 위한 O(1) 조기 종료 루프 적용

.jules/bolt.md

@@ -61,3 +61,7 @@
 ## 2026-07-13 - Array.from mapping optimization
 **Learning:** Using `Array.from({ length: N }).map(...)` creates an intermediate array of `undefined` values which requires memory allocation and garbage collection, adding O(N) unnecessary overhead in frequently re-rendered UI components.
 **Action:** Use `Array.from({ length: N }, (_, index) => ...)` to map elements directly during array creation, avoiding intermediate allocations.
+
+## 2026-08-10 - Array density check optimization
+**Learning:** Using `Array.from().every()` to check for array density creates O(N) intermediate array allocations which add unnecessary garbage collection overhead on the critical path.
+**Action:** Use a standard for-loop with an early return for an O(1) memory and faster check.

apps/desktop/src/features/score/scoreStorage.test.ts

@@ -32,4 +32,24 @@ describe("scoreStorage bridge resolution", () => {
       BRIDGE_UNAVAILABLE_MESSAGE
     );
   });
+  it("uses the fallback loop for array density checking", async () => {
+    const tauriWindow = window as TauriWindow;
+    tauriWindow.__TAURI_INVOKE__ = vi.fn().mockResolvedValue([1, 2, 3]);
+
+    const result = await readScorePdf("project-1", "score-1");
+    expect(result).toBeInstanceOf(Uint8Array);
+    expect(result.length).toBe(3);
+    expect(result[0]).toBe(1);
+    expect(result[1]).toBe(2);
+    expect(result[2]).toBe(3);
+  });
+
+  it("fails array density check if non-number elements are present", async () => {
+    const tauriWindow = window as TauriWindow;
+    tauriWindow.__TAURI_INVOKE__ = vi.fn().mockResolvedValue([1, "two", 3]);
+
+    await expect(readScorePdf("project-1", "score-1")).rejects.toThrow(
+      "Invalid score bridge response"
+    );
+  });
 });

apps/desktop/src/features/score/scoreStorage.ts

@@ -91,8 +91,19 @@ export async function readScorePdf(projectId: string, scoreId: string): Promise<
   if (response instanceof ArrayBuffer) {
     return new Uint8Array(response);
   }
-  if (Array.isArray(response) && response.every((byte) => typeof byte === "number")) {
-    return Uint8Array.from(response as number[]);
+  if (Array.isArray(response)) {
+    // 성능 최적화: O(N) 콜백 호출 오버헤드를 줄이기 위해 for 루프 사용
+    let isNumberArray = true;
+    for (let i = 0; i < response.length; i++) {
+      if (typeof response[i] !== "number") {
+        isNumberArray = false;
+        break;
+      }
+    }
+
+    if (isNumberArray) {
+      return Uint8Array.from(response as number[]);
+    }
   }
 
   throw new Error(INVALID_RESPONSE_MESSAGE);