diff --git a/packages/frontend/src/local-storage.ts b/packages/frontend/src/local-storage.ts
index 5b8ba77e01..5ca25dc5d9 100644
--- a/packages/frontend/src/local-storage.ts
+++ b/packages/frontend/src/local-storage.ts
@@ -44,16 +44,45 @@ export type Keys =
 // セッション毎に廃棄されるLocalStorage代替（セーフモードなどで使用できそう）
 //const safeSessionStorage = new Map<Keys, string>();
 
+
+/**
+ * A utility object for interacting with the browser's localStorage.
+ *
+ * It's mostly a small wrapper around window.localStorage, but it validates
+ * keys with a typesafe enum, and provides a few convenience methods for JSON.
+ */
 export const miLocalStorage = {
+	/**
+	 * Retrieves an item from localStorage.
+	 * @param {Keys} key - The key of the item to retrieve.
+	 * @returns {string | null} The value of the item, or null if the item does not exist.
+	 */
 	getItem: (key: Keys): string | null => {
 		return window.localStorage.getItem(key);
 	},
+
+	/**
+	 * Stores an item in localStorage.
+	 * @param {Keys} key - The key of the item to store.
+	 * @param {string} value - The value of the item to store.
+	 */
 	setItem: (key: Keys, value: string): void => {
 		window.localStorage.setItem(key, value);
 	},
+
+	/**
+	 * Removes an item from localStorage.
+	 * @param {Keys} key - The key of the item to remove.
+	 */
 	removeItem: (key: Keys): void => {
 		window.localStorage.removeItem(key);
 	},
+
+	/**
+	 * Retrieves an item from localStorage and parses it as JSON.
+	 * @param {Keys} key - The key of the item to retrieve.
+	 * @returns {any | undefined} The parsed value of the item, or undefined if the item does not exist.
+	 */
 	getItemAsJson: (key: Keys): any | undefined => {
 		const item = miLocalStorage.getItem(key);
 		if (item === null) {
@@ -61,6 +90,12 @@ export const miLocalStorage = {
 		}
 		return JSON.parse(item);
 	},
+
+	/**
+	 * Stores an item in localStorage as a JSON string.
+	 * @param {Keys} key - The key of the item to store.
+	 * @param {any} value - The value of the item to store.
+	 */
 	setItemAsJson: (key: Keys, value: any): void => {
 		miLocalStorage.setItem(key, JSON.stringify(value));
 	},