improve performance

packages/backend/src/misc/clone.ts

@@ -0,0 +1,18 @@
+// structredCloneが遅いため
+// SEE: http://var.blog.jp/archives/86038606.html
+
+type Cloneable = string | number | boolean | null | { [key: string]: Cloneable } | Cloneable[];
+
+export function deepClone<T extends Cloneable>(x: T): T {
+	if (typeof x === 'object') {
+		if (x === null) return x;
+		if (Array.isArray(x)) return x.map(deepClone) as T;
+		const obj = {} as Record<string, Cloneable>;
+		for (const [k, v] of Object.entries(x)) {
+			obj[k] = deepClone(v);
+		}
+		return obj as T;
+	} else {
+		return x;
+	}
+}