diff --git a/packages/frontend/src/scripts/merge.ts b/packages/frontend/src/scripts/merge.ts
index aba49adc79..b9fb449784 100644
--- a/packages/frontend/src/scripts/merge.ts
+++ b/packages/frontend/src/scripts/merge.ts
@@ -7,10 +7,10 @@ import { deepClone } from './clone.js';
 import type { Cloneable } from './clone.js';
 
 export type DeepPartial<T> = {
-	[P in keyof T]?: T[P] extends Record<string | number | symbol, unknown> ? DeepPartial<T[P]> : T[P];
+	[P in keyof T]?: T[P] extends Record<PropertyKey, unknown> ? DeepPartial<T[P]> : T[P];
 };
 
-function isPureObject(value: unknown): value is Record<string | number | symbol, unknown> {
+function isPureObject(value: unknown): value is Record<PropertyKey, unknown> {
 	return typeof value === 'object' && value !== null && !Array.isArray(value);
 }
 
@@ -18,14 +18,14 @@ function isPureObject(value: unknown): value is Record<string | number | symbol,
  * valueにないキーをdefからもらう（再帰的）\
  * nullはそのまま、undefinedはdefの値
  **/
-export function deepMerge<X extends Record<string | number | symbol, unknown>>(value: DeepPartial<X>, def: X): X {
+export function deepMerge<X extends Record<PropertyKey, unknown>>(value: DeepPartial<X>, def: X): X {
 	if (isPureObject(value) && isPureObject(def)) {
 		const result = deepClone(value as Cloneable) as X;
 		for (const [k, v] of Object.entries(def) as [keyof X, X[keyof X]][]) {
 			if (!Object.hasOwn(value, k) || value[k] === undefined) {
 				result[k] = v;
 			} else if (isPureObject(v) && isPureObject(result[k])) {
-				const child = deepClone(result[k] as Cloneable) as DeepPartial<X[keyof X] & Record<string | number | symbol, unknown>>;
+				const child = deepClone(result[k] as Cloneable) as DeepPartial<X[keyof X] & Record<PropertyKey, unknown>>;
 				result[k] = deepMerge<typeof v>(child, v);
 			}
 		}