{"id":1310,"date":"2023-02-25T15:49:08","date_gmt":"2023-02-25T06:49:08","guid":{"rendered":"http:\/\/attacktube.com\/?p=1310"},"modified":"2023-02-26T10:08:12","modified_gmt":"2023-02-26T01:08:12","slug":"%e3%80%90javascript%e3%80%91%e5%8d%b3%e6%99%82%e9%96%a2%e6%95%b0%e3%81%a8this","status":"publish","type":"post","link":"https:\/\/attacktube.com\/?p=1310","title":{"rendered":"\u3010JavaScript\u3011\u5373\u6642\u95a2\u6570\u3068this"},"content":{"rendered":"\n<p>IIFE\u306f\u5b9a\u7fa9\u3055\u308c\u308b\u3068\u3059\u3050\u306b\u5b9f\u884c\u3055\u308c\u308b\u3002<br>\u5373\u6642\u95a2\u6570\u306e\u4e2d\u306ethis\u306b\u306f\u30b0\u30ed\u30fc\u30d0\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u30bb\u30c3\u30c8\u3055\u308c\u308b\u3053\u3068\u306b\u6ce8\u610f\u3059\u308b\u3002<br>\u6b21\u306b\u3088\u3046\u306a\u6319\u52d5\u306b\u306a\u308b\u3002<br>bind\u3001apply\u3001call\u3092\u4f7f\u3063\u3066this\u306e\u5024\u3092\u30b3\u30f3\u30c8\u30ed\u30fc\u30eb\u3059\u308b\u3002<\/p>\n\n\n\n<!--more-->\n\n\n\n<pre><code>\nvar value = \"GlobalRed\",\n    ob = {};\nob.value = \"blue\";\n\nob.abc = function() {\n    console.log(\"1:this.value=\" + this.value);\n};\n\nob.abc(); \/\/blue\n\nvar ob2 = ob.abc;\n\n\/\/\u3053\u306e\u6642\u3001this\u304c\u30b0\u30ed\u30fc\u30d0\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3067\u3042\u308b\u3053\u3068\u306b\u6ce8\u610f\u3059\u308b\u3002\nob2(); \/\/GlobalRed\n\nconst ob3 = ob2.bind(ob);\n\nob3(); \/\/blue\n\nconst ob4 = ob.abc.bind(ob);\n\nob4(); \/\/blue\n\n\n\/\/\u5373\u6642\u5b9f\u884c\u95a2\u6570\u5f0f(Immediately-invoked function expression : IIFE)\nob.abc2 = (function() {\n    console.log(\"2:this.value=\" + this.value); \/\/GlobalRed\n})();\n\n\/\/\u5bfe\u51e6\u65b9\u6cd5 \u305d\u306e1\n\/\/call\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u3046\nob.abc3 = (function() {\n    console.log(\"3:this.value=\" + this.value); \/\/blue\n}).call(ob);\n\n\/\/\u5bfe\u51e6\u65b9\u6cd5 \u305d\u306e2 \n\/\/apply\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u3046\nob.abc4 = (function() {\n    console.log(\"4:this.value=\" + this.value); \/\/blue\n}).apply(ob);\n\n\/\/\u5bfe\u51e6\u65b9\u6cd5 \u305d\u306e3\n\/\/this\u3067\u306a\u304fob\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u3092\u4f7f\u3046\nob.abc5 = (function() {\n    console.log(\"5:ob.value=\" + ob.value); \/\/blue\n})();\n\n\/\/\u5373\u6642\u95a2\u6570\u3068\u30af\u30ed\u30fc\u30b8\u30e3\u3068this(\u305d\u306e1)\nob.abc6 = (function() {\n\n    var that = {};\n    that.value = \"black\";\n    \/\/this\u306b\u306f\u30b0\u30ed\u30fc\u30d0\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u30bb\u30c3\u30c8\u3055\u308c\u3066\u3044\u308b\n    console.log(\"6-1:this.value=\" + this.value); \/\/GlobalRed\n\n    that.a1 = function() {\n        console.log(\"6-2:this.value=\" + this.value); \/\/black\n    };\n\n    return that;\n\n})();\n\nob.abc6.a1();\n\n\/\/\u5373\u6642\u95a2\u6570\u3068\u30af\u30ed\u30fc\u30b8\u30e3\u3068this(\u305d\u306e2)\nob.abc7 = (function() {\n    \/\/this\u306b\u306f\u30b0\u30ed\u30fc\u30d0\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u304c\u30bb\u30c3\u30c8\u3055\u308c\u3066\u3044\u308b\n    \/\/\u3053\u308c\u306f\u3084\u3063\u3066\u306f\u30c0\u30e1\u306a\u30d1\u30bf\u30fc\u30f3\n    var that = this;\n    that.value = \"black\";\n    \/\/\u3053\u308c\u306f\u30b0\u30ed\u30fc\u30d0\u30eb\u306aa1\u95a2\u6570\u3092\u5b9a\u7fa9\u3057\u3066\u3044\u308b\u3053\u3068\u306b\u306a\u308b\u3002\n    \/\/\u30b0\u30ed\u30fc\u30d0\u30eb\u95a2\u6570\u3092\u5b9a\u7fa9\u3057\u306a\u3044\u305f\u3081\u306b\u30af\u30ed\u30fc\u30b8\u30e3\u3092\u4f7f\u7528\u3057\u3066\u3044\u308b\u306e\u306b\n    \/\/\u30b0\u30ed\u30fc\u30d0\u30eb\u95a2\u6570\u3092\u5b9a\u7fa9\u3057\u3066\u306f\u30c0\u30e1\u3002\n    that.a1 = function() {\n        console.log(\"7:this.value=\" + this.value); \/\/black\n    };\n\n    return that;\n\n})();\n\na1(); \/\/GlobalRed\n\/\/\u5373\u6642\u95a2\u6570\u3068\u30af\u30ed\u30fc\u30b8\u30e3\u3068this(\u305d\u306e3)\nob.abc8 = (function() {\n\n    var that = {};\n    that.value = \"black\";\n\n    console.log(\"8-1:this.value=\" + this.value); \/\/blue\n\n    \/\/bind\u3067\n    that.a1 = function() {\n        console.log(\"8-2:this.value=\" + this.value); \/\/blue\n    }.bind(this);\n\n    return that;\n\n}).apply(ob);\n\nob.abc8.a1(); \/\/blue\n\n\/\/\u5373\u6642\u95a2\u6570\u306e\u4e2d\u306bstrict\u30e2\u30fc\u30c9\u3092\u4f7f\u3063\u305f\u5834\u5408(1)\nob.abc9 = (function() {\n    \"use strict\";\n    var that = {};\n    that.value = \"black\";\n    console.log(\"9-1:this=\" + this); \/\/undefined\n\n    that.a1 = function() {\n        console.log(\"9-2:this.value=\" + this.value); \/\/black\n    };\n\n    return that;\n\n})();\n\nob.abc9.a1();\n\n\/\/\u5373\u6642\u95a2\u6570\u306e\u4e2d\u306bstrict\u30e2\u30fc\u30c9\u3092\u4f7f\u3063\u305f\u5834\u5408(2)\nob.abc10 = (function() {\n    \"use strict\";\n    var that = {};\n    that.value = \"black\";\n    console.log(\"10-1:this.value=\" + this.value); \/\/blue\n\n    that.a1 = function() {\n        console.log(\"10-2:this.value=\" + this.value); \/\/blue\n    }.bind(this);\n\n    return that;\n\n}).apply(ob);\n\nob.abc10.a1();\n\n\/*\n\n1:this.value=blue\n1:this.value=GlobalRed\n1:this.value=blue\n2:this.value=GlobalRed\n3:this.value=blue\n4:this.value=blue\n5:ob.value=blue\n6-1:this.value=GlobalRed\n6-2:this.value=black\n7:this.value=black\n8-1:this.value=blue\n8-2:this.value=blue\n9-1:this=undefined\n9-2:this.value=black\n10-1:this.value=blue\n10-2:this.value=blue\n\n*\/\n\n<\/code><\/pre>\n\n\n\n<br>\n<script async=\"\" src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-3461056110605997\" crossorigin=\"anonymous\"><\/script>\n<ins class=\"adsbygoogle\" style=\"display:block; text-align:center;\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\" data-ad-client=\"ca-pub-3461056110605997\" data-ad-slot=\"3137443461\"><\/ins>\n<script>\n     (adsbygoogle = window.adsbygoogle || []).push({});\n<\/script>\n<br>\n\n\n\n<p>\u300c\u5373\u6642\u95a2\u6570\u300d\u3068\u3044\u3046\u547c\u3073\u65b9\u306f\u3001<a href=\"https:\/\/www.oreilly.co.jp\/books\/9784873114880\/\">O&#8217;Reilly Japan &#8211; 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