{"image_url":null,"description":"\u25a0 \u306f\u3058\u3081\u306b ! \u3068\u304b ? \u3068\u304b\u306e\u52d5\u304d\u304c\u3084\u3084\u3063\u3053\u3057\u304b\u3063\u305f\u306e\u3067\u30e1\u30e2\u3002 \u76ee\u6b21 \u3010\uff10\u3011\u5b9f\u884c\u74b0\u5883 \u3010\uff11\u3011\uff1f \uff11\uff09\u30aa\u30d7\u30b7\u30e7\u30f3\u5f15\u6570 (optional parameter) \uff12\uff09\u30aa\u30d7\u30b7\u30e7\u30ca\u30eb\u30c1\u30a7\u30a4\u30cb\u30f3\u30b0 (Optional chaining) '?.' \uff13\uff09\u4e09\u9805\u6f14\u7b97\u5b50 \uff14\uff09Null \u5408\u4f53\u6f14\u7b97\u5b50 (nullish Coalescing) '??' \u3010\uff12\u3011\uff01 \uff11\uff09\u975enull\u30a2\u30b5\u30fc\u30b7\u30e7\u30f3\u6f14\u7b97\u5b50 (Non-null assertion operator) \u3010\uff10\u3011\u5b9f\u884c\u74b0\u5883 * \u30d6\u30e9\u30a6\u30b6\u3067\u5b9f\u884c\u3067\u304d\u308b https://www.typescriptlang.org/play \u3010\uff11\u3011\uff1f \uff11\uff09\u30aa\u30d7\u30b7\u30e7\u30f3\u5f15\u6570 (optiona\u2026","blog_url":"https://dk521123.hatenablog.com/","author_url":"https://blog.hatena.ne.jp/dk521123/","provider_name":"Hatena Blog","blog_title":"\u30d7\u30ed\u30b0\u30e9\u30e0 \u306e\u8d85\u500b\u4eba\u7684\u306a\u30e1\u30e2","height":"190","title":"\u3010JS\u3011\u3010TS\u3011\u8a18\u53f7\u306e\u6f14\u7b97\u5b50 \uff5e  ? / ?? / ! \uff5e","version":"1.0","author_name":"dk521123","url":"https://dk521123.hatenablog.com/entry/2022/03/21/234932","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fdk521123.hatenablog.com%2Fentry%2F2022%2F03%2F21%2F234932\" title=\"\u3010JS\u3011\u3010TS\u3011\u8a18\u53f7\u306e\u6f14\u7b97\u5b50 \uff5e  ? / ?? / ! \uff5e - \u30d7\u30ed\u30b0\u30e9\u30e0 \u306e\u8d85\u500b\u4eba\u7684\u306a\u30e1\u30e2\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","type":"rich","categories":["TypeScript","JavaScript"],"published":"2022-03-21 23:49:32","provider_url":"https://hatena.blog","width":"100%"}