const obj = { hoge: [new Date(2023, 3, 12), 1], fuga: 'foo' }; const objClone = structuredClone(obj); // ディープコピー obj.hoge[1] = 10; console.log(objClone.hoge[1]); // 1 objClone.hoge[0].setFullYear(2050); console.log(obj.hoge[0].getFullYear()); // 2023
![オブジェクトのクローンにJSON化を使う時代は終わった!【JavaScript】 - Qiita](https://cdn-ak-scissors.b.st-hatena.com/image/square/0f451d5754535494edd7497685957cc5ace43bb8/height=288;version=1;width=512/https%3A%2F%2Fqiita-user-contents.imgix.net%2Fhttps%253A%252F%252Fcdn.qiita.com%252Fassets%252Fpublic%252Farticle-ogp-background-412672c5f0600ab9a64263b751f1bc81.png%3Fixlib%3Drb-4.0.0%26w%3D1200%26mark64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-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%26mark-x%3D142%26mark-y%3D57%26blend64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZoPTc2Jnc9NzcwJnR4dD0lNDBzaWxhbmUxMDAxJnR4dC1jb2xvcj0lMjMxRTIxMjEmdHh0LWZvbnQ9SGlyYWdpbm8lMjBTYW5zJTIwVzYmdHh0LXNpemU9MzYmdHh0LWFsaWduPWxlZnQlMkN0b3Amcz05NWEzOWIwNTc2OTZiYTZiMTBiZWJhZWQ3YWVmZTkyZQ%26blend-x%3D142%26blend-y%3D486%26blend-mode%3Dnormal%26s%3Dfed32a3f9a3e3479b2f4bf8e62fb83a2)