{"categories":["JavaScript"],"title":"\u5426\u5b9a\u6f14\u7b97\u5b50(!)\u30922\u56de\u4f7f\u3063\u3066undefined\u3084null\u5224\u5b9a\u3092\u884c\u3046","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Foooomincrypto.hatenadiary.jp%2Fentry%2F2022%2F09%2F24%2F230413\" title=\"\u5426\u5b9a\u6f14\u7b97\u5b50(!)\u30922\u56de\u4f7f\u3063\u3066undefined\u3084null\u5224\u5b9a\u3092\u884c\u3046 - \u304a\u30fc\u307f\u3093\u30d6\u30ed\u30b0\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","url":"https://oooomincrypto.hatenadiary.jp/entry/2022/09/24/230413","provider_url":"https://hatena.blog","version":"1.0","author_url":"https://blog.hatena.ne.jp/bookreadkun/","blog_title":"\u304a\u30fc\u307f\u3093\u30d6\u30ed\u30b0","image_url":null,"height":"190","provider_name":"Hatena Blog","published":"2022-09-24 23:04:13","type":"rich","author_name":"bookreadkun","blog_url":"https://oooomincrypto.hatenadiary.jp/","description":"\u306f\u3058\u3081\u306b \u5426\u5b9a\u6f14\u7b97\u5b50\u30922\u56de\u4f7f\u3063\u3066undefined\u3084null\u5224\u5b9a\u3092\u884c\u3046\u51e6\u7406\u3092\u898b\u308b\u6a5f\u4f1a\u304c\u3042\u3063\u305f\u306e\u3067\u5099\u5fd8\u9332\u3068\u3057\u3066\u6b8b\u3057\u307e\u3059\u3002 \u30b5\u30f3\u30d7\u30eb\u30b3\u30fc\u30c9 \u4f7f\u3046\u5834\u9762\u306f\u5c11\u3057\u9650\u3089\u308c\u3066\u304d\u307e\u3059\u304c\u3001\u4f8b\u3048\u3070\u4e09\u9805\u6f14\u7b97\u5b50\u3092\u7528\u3044\u308b\u3068\u304d\u306b\u5024\u304cundefined\u3067\u306f\u306a\u3044\u304b\u3067\u6761\u4ef6\u5206\u5c90\u3092\u884c\u3046\u3068\u3057\u307e\u3059(null\u3067\u3082\u540c\u69d8\u306e\u52d5\u304d\u306b\u306a\u308a\u307e\u3059)\u3002 \u901a\u5e38\u306a\u3089\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u66f8\u304f\u304b\u3068\u601d\u3044\u307e\u3059\u3002 let a; const b = a !== undefined ? 'not undefined' : 'undefined'; \u4e0a\u8a18\u3067\u3082\u826f\u3044\u306e\u3067\u3059\u304c\u3001\u5426\u5b9a\u6f14\u7b97\u5b50\u30922\u56de\u5229\u7528\u3057\u3066(!!)\u5224\u5b9a\u3059\u308b\u3053\u3068\u3082\u53ef\u80fd\u3067\u3059\u3002 let a; const b = !!a ? 'not\u2026","width":"100%"}