{"id":3015,"date":"2013-08-27T09:25:44","date_gmt":"2013-08-27T00:25:44","guid":{"rendered":"https:\/\/gunmagisgeek.com\/wordpress\/?p=3015"},"modified":"2013-12-30T21:49:32","modified_gmt":"2013-12-30T12:49:32","slug":"post-3015","status":"publish","type":"post","link":"https:\/\/gunmagisgeek.com\/blog\/javascript\/3015","title":{"rendered":"JavaScript\u306e\u697d\u3057\u3044(?)\u3068\u3053\u308d\u306e\u89e3\u8aac"},"content":{"rendered":"

\"iluvjavascript\"<\/p>\n

Qiita\u306b\u300cJavaScript\u306e\u697d\u3057\u3044(?)\u3068\u3053\u308d<\/a>\u300d\u3068\u3044\u3046\u8a18\u4e8b\u3092\u6295\u7a3f\u3057\u305f\u306e\u3067\u3001\u305d\u306e\u5185\u5bb9\u3092\u3061\u3087\u3063\u3068\u3060\u3051\u89e3\u8aac\u3057\u3066\u307f\u307e\u3059\u3002
\nJavaScript\u306e\u5947\u5947\u602a\u602a\u306a\u4ed5\u69d8\u306b\u3064\u3044\u3066\u306f\u7406\u89e3\u3067\u304d\u3066\u3044\u308b\u81ea\u4fe1\u304c\u306a\u3044\u306e\u3067\u3001\u5618\u66f8\u3044\u3066\u3044\u308b\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u3002<\/p>\n

\u914d\u5217\u306e\u6dfb\u3048\u5b57<\/h2>\n
var a = ["hello", "world", "hoge"];\na[0] \/\/->"hello"\na["0"] \/\/->"hello"\n<\/pre>\n
Javascript\u306e\u914d\u5217\u3067\u306f\u6dfb\u3048\u5b57\u3092\u6570\u5024\u3067\u6307\u5b9a\u3057\u3066\u3082\u6587\u5b57\u3067\u6307\u5b9a\u3057\u3066\u3082\u540c\u3058\u5024\u304c\u8fd4\u3063\u3066\u304d\u307e\u3059\u3002
\n\u6dfb\u3048\u5b57\u306e\u52a0\u7b97\u3084\u6587\u5b57\u7d50\u5408\u306a\u3069\u3082\u3067\u304d\u307e\u3059\u3002<\/p>\n
var a = ["zero","one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve"]\n\na[1+1] \/\/-> "two"\na["1"+"1"] \/\/->"eleven"\n<\/pre>\n
JavaScript\u3067\u306f\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3082\u3042\u308b\u610f\u5473\u9023\u60f3\u914d\u5217\u306a\u306e\u3067\u3001\u30e1\u30bd\u30c3\u30c9\u3082\u914d\u5217\u306e\u6dfb\u3048\u5b57\u3068\u3057\u3066\u547c\u3073\u51fa\u305b\u307e\u3059\u3002<\/p>\n
["hello", "world", "hoge"].pop() \/\/->"hoge"\n["hello", "world", "hoge"]['pop']() \/\/->"hoge"\n<\/pre>\n
\u4e0d\u601d\u8b70\u3067\u3059\u306d\u3002<\/p>\n
valueOf\u30e1\u30bd\u30c3\u30c9<\/h2>\n
var a = {};\na.valueOf = function(){ alert('valueOf\u30e1\u30c3\u30bd\u30c9\u304c\u547c\u3070\u308c\u305f\u3088\uff01')}\na + 1 \/\/->alert\u5b9f\u884c\n<\/pre>\n
valueOf\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u6697\u9ed9\u306e\u578b\u5909\u63db\u304c\u884c\u308f\u308c\u308b\u969b\u306b\u3088\u3073\u3060\u3055\u308c\u307e\u3059\u3002
\n\u305d\u306e\u7279\u6027\u3092\u4f7f\u3063\u3066\u3001\u6697\u9ed9\u306e\u578b\u5909\u63db\u3092\u6291\u5236\u3059\u308b\u30c6\u30af\u30cb\u30c3\u30af\u3082\u3042\u308b\u305d\u3046\u3067\u3059\u3002
\n\u5b9f\u7528\u7684\u304b\u3069\u3046\u304b\u306f\u308f\u304b\u308a\u307e\u305b\u3093\u304c\u2026\u2026<\/p>\n
var obj = {}\n"test" + obj \/\/-> "test[object Object]"\nvar fnc = function(){}\n"test" + fnc \/\/-> "testfunction (){}"\n\n\/\/\u6697\u9ed9\u306e\u578b\u5909\u63db\u3092\u6291\u5236\nObject.prototype.valueOf = function () {\n    throw new Error('\u578b\u304c\u9055\u3063\u3066\u308b\u3088\uff01');\n};\n\n"test" + obj \/\/-> Uncaught Error: \u578b\u304c\u9055\u3063\u3066\u308b\u3088\uff01 \n"test" + fnc \/\/-> Uncaught Error: \u578b\u304c\u9055\u3063\u3066\u308b\u3088\uff01 \n<\/pre>\n
\u8a55\u4fa1\u3055\u308c\u308b\u305f\u3073\u306b\u30e9\u30f3\u30c0\u30e0\u3067\u5024\u3092\u8fd4\u3059\u914d\u5217\u3068\u3044\u3046\u308f\u3051\u306e\u308f\u304b\u3089\u306a\u3044\u3082\u306e\u3082\u3064\u304f\u3063\u3066\u307f\u307e\u3057\u305f\u3002<\/p>\n
var a = ["hello", "world", "hoge", "xxx", "test", "boo"];\nvar b = {};\nb.valueOf = function(){ return  Math.floor(Math.random() * 5) }\na[b+0]\n\/\/->"world"\na[b+0]\n\/\/->"test"\na[b+0]\n\/\/->"xxx"\na[b+0]\n\/\/->"test"\n<\/pre>\n
Qiita\u306e\u30b3\u30e1\u30f3\u30c8\u6b04\u3067\u6559\u3048\u3066\u3044\u305f\u3060\u3044\u305f\u306e\u3067\u3059\u304c\u3001toString\u30e1\u30bd\u30c3\u30c9\u3092\u4e0a\u66f8\u304d\u3059\u308b\u65b9\u304c\u304d\u308c\u3044\u306b\u66f8\u3051\u307e\u3059\u3002<\/p>\n
var a = ["hello", "world", "hoge", "xxx", "test", "boo"];\nvar b = {};\nb.toString = function(){return ~~(Math.random() * 5); };\na[b]\n\/\/->"world"\n<\/pre>\n
\u914d\u5217\u306e\u6dfb\u3048\u5b57\u306b\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u6307\u5b9a\u3059\u308b\u3068toString\u304c\u547c\u3070\u308c\u308b\u307f\u305f\u3044\u3067\u3059\u3002\u77e5\u3089\u306a\u304b\u3063\u305f\u3002JavaScript\u5965\u304c\u6df1\u3044\u2026\u2026<\/p>\n
\u6dfb\u3048\u5b57\u3067\u4e09\u9805\u6f14\u7b97\u5b50<\/h2>\n
\u6dfb\u3048\u5b57\u306e\u4e2d\u3067\u4e09\u9805\u6f14\u7b97\u5b50\u3082\u4f7f\u3048\u307e\u3059\u3002<\/p>\n
a = ["aaa", "bbb" , "ccc", "ddd"];\nflag = true;\na[flag ? 'shift' : 'pop']();\n\/\/->"aaa"\n\nflag = false;\na[flag ? 'shift' : 'pop']();\n\/\/->"ddd"\n<\/pre>\n
\u6dfb\u3048\u5b57\u3067\u30e1\u30bd\u30c3\u30c9\u306e\u547c\u3073\u51fa\u3057\u304c\u3067\u304d\u308b\u306e\u3067\u3001\u4e09\u9805\u6f14\u7b97\u5b50\u3068\u7d44\u307f\u5408\u308f\u305b\u3066\u4f7f\u3046\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002
\n\u4f7f\u3044\u3069\u3053\u308d\u304c\u308f\u304b\u308a\u307e\u305b\u3093\u304c\u2026\u2026<\/p>\n
JavaScript\u3063\u3066\u30db\u30f3\u30c8\u697d\u3057\u3044\u3067\u3059\u306d!<\/p>\n","protected":false},"excerpt":{"rendered":"
Qiita\u306b\u300cJavaScript\u306e\u697d\u3057\u3044(?)\u3068…<\/p>\n","protected":false},"author":1,"featured_media":3016,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-3015","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-javascript","has-post-thumbnail-archive"],"_links":{"self":[{"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/posts\/3015","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/comments?post=3015"}],"version-history":[{"count":1,"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/posts\/3015\/revisions"}],"predecessor-version":[{"id":3257,"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/posts\/3015\/revisions\/3257"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/media\/3016"}],"wp:attachment":[{"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/media?parent=3015"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/categories?post=3015"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gunmagisgeek.com\/blog\/wp-json\/wp\/v2\/tags?post=3015"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}