{"html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fwww.pandanoir.info%2Fentry%2F2019%2F02%2F05%2F190000\" title=\"\u3069\u3093\u306a\u6df1\u3055\u306e\u914d\u5217\u30821\u6b21\u5143\u914d\u5217\u306b\u3059\u308b - Panda Noir\" 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","image_url":"https://cdn-ak.f.st-hatena.com/images/fotolife/p/panda_noir/20180102/20180102122627.png","author_name":"panda_noir","categories":["JavaScript","ES2019"],"author_url":"https://blog.hatena.ne.jp/panda_noir/","blog_title":"Panda Noir","published":"2019-02-05 19:00:00","blog_url":"https://www.pandanoir.info/","version":"1.0","height":"190","title":"\u3069\u3093\u306a\u6df1\u3055\u306e\u914d\u5217\u30821\u6b21\u5143\u914d\u5217\u306b\u3059\u308b","provider_name":"Hatena Blog","description":"ES2019\u3067Array#flatMap\u304c\u5c0e\u5165\u3055\u308c\u305f\u306e\u3067\u3001\u305d\u308c\u3092\u4f7f\u3063\u3066\u3069\u3093\u306a\u6df1\u3055\u306e\u914d\u5217\u3067\u30821\u6b21\u5143\u306b\u3059\u308b\u65b9\u6cd5\u3092\u7d39\u4ecb\u3057\u307e\u3059\u3002 flatMap\u306e\u4ed5\u69d8 flatMap\u306fmap()\u3057\u3066\u304b\u3089flat()\u3059\u308b\u30e1\u30bd\u30c3\u30c9\u3067\u3059\u3002 [1,2,3].map(n => [n,-n]); // [[1,-1],[2,-2],[3,-3]] [[1,-1],[2,-2],[3,-3]].flat(); // [1,-1,2,-2,3,-3] [1,2,3].flatMap(n => [n,-n]); // [1,-1,2,-2,3,-3] flatMap\u3092\u4f7f\u3063\u30661\u6b21\u5143\u306b\u3059\u308b \u30b3\u30fc\u30c9 flatMap\u3092\u4f7f\u3063\u3066\u3001\u3069\u3093\u306a\u6df1\u3055\u306e\u914d\u5217\u2026","provider_url":"https://hatena.blog","url":"https://www.pandanoir.info/entry/2019/02/05/190000","width":"100%"}