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 * ローカルストレージからデータをロードする
 * @param fileKey 対応するデータのキー文字列
function loadLocalStorage(fileKey)
    if (!window.localStorage)
        return undefined; // localStorage非対応ならundefinedを返す
    const data = window.localStorage.getItem(fileKey); // fileKeyに対応する文字列を返す
    if (!data)
        return undefined; // 読み込むものがないならundefinedを返す
    return data; //

 * ローカルストレージにデータを保存する
 * @param fileKey 保存するデータのキー文字列
 * @param dataStr 保存するデータの文字列 
function saveLocalStorage(fileKey, dataStr)
    if (!window.localStorage)
        return false; // 保存できないのならfalseを返す
    window.localStorage.setItem(fileKey, dataStr); // localStorageにデータを保存する


// 保存するデータ構造を定義
const dataStructure = {
    "aryData": [0, 1, 2, 3],
    "str": "testtest",
    "position": { x: 0, y: 0 }
// JSONでデータ構造を文字列化する
const dataStructureStr = JSON.stringify(dataStructure);

saveLocalStorage("key_string1", dataStructureStr);
const loadStr1 = loadLocalStorage("key_string1");

// 読み込んだJSON文字列の表示

// JSON文字列をデータ構造に復元する
const restoreDataStructure = JSON.parse(loadStr1);

// コンソールにデータを表示
console.log(`データ構造の中身 ary[1]: ${restoreDataStructure.aryData[1]}`);
console.log(`データ構造の中身 str: ${restoreDataStructure.str}`);
console.log(`データ構造の中身 position x: ${restoreDataStructure.position.x}`);