{"id":2697,"date":"2017-01-10T06:35:39","date_gmt":"2017-01-09T21:35:39","guid":{"rendered":"http:\/\/stuffy.dip.jp\/wordpress\/?p=2697"},"modified":"2017-05-29T16:15:30","modified_gmt":"2017-05-29T07:15:30","slug":"declaring-variables-and-error","status":"publish","type":"post","link":"https:\/\/www.stuffy.site\/wordpress\/?p=2697","title":{"rendered":"\u5909\u6570\u306e\u5ba3\u8a00\u3068\u30a8\u30e9\u30fc"},"content":{"rendered":"

\u4eca\u56de\u306f\u300eJavaScript \u7b2c6\u7248\u300fDavid Flanagan (\u8457),\u00a0\u00a0\u00a0 \u6751\u4e0a \u5217 (\u7ffb\u8a33)\u00a0<\/span><\/a>\u00a0\u304b\u3089\u4e88\u7d04\u8a9e\u3001var \u306e\u7701\u7565\u3001\u5024\u306e\u4ee3\u5165\u524d\u306e\u5909\u6570\u306e\u53c2\u7167\u3001\u5909\u6570\u306e\u4e0a\u66f8\u304d\u306a\u3069\u521d\u6b69\u7684\u306aJavaScript \u306e\u6319\u52d5\u306b\u3064\u3044\u3066\u629c\u7c8b\u3057\u307e\u3057\u305f\u3002(var \u306e\u8a9e\u6e90\u306fvariable\u304b\u3089\u3060\u305d\u3046\u3067\u3059\u3002)<\/p>\n

2.4.1\u3000\u4e88\u7d04\u8a9e<\/strong>
\nJavaScript \u306b\u306f\u4e88\u7d04\u8a9e\u304c\u305f\u304f\u3055\u3093\u3042\u308a\u307e\u3059\u3002\u4ee5\u4e0b\u306b\u6319\u3052\u308b\u3088\u3046\u306a\u5358\u8a9e\u306f\u3001\u30d7\u30ed\u30b0\u30e9\u30e0\u4e2d\u3067\u8b58\u5225\u5b50\u3068\u3057\u3066\u4f7f\u3046\u3053\u3068\u306f\u3067\u304d\u307e\u305b\u3093\u3002<\/span><\/em><\/p>\n\n\n\n\n\n\n\n\n
break<\/td>\ndelete<\/td>\nfunction<\/td>\nreturn<\/td>\ntypeof<\/td>\n<\/tr>\n
case<\/td>\ndo<\/td>\nif<\/td>\nswitch<\/td>\nvar<\/td>\n<\/tr>\n
catch<\/td>\nelse<\/td>\nin<\/td>\nthis<\/td>\nvoid<\/td>\n<\/tr>\n
continue<\/td>\nfalse<\/td>\ninstanceof<\/td>\nthrow<\/td>\nwhile<\/td>\n<\/tr>\n
debugger<\/td>\nfinally<\/td>\nnew<\/td>\ntrue<\/td>\nwith<\/td>\n<\/tr>\n
default<\/td>\nfor<\/td>\nnull<\/td>\ntry<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u3055\u3089\u306b\u3001\u4ee5\u4e0b\u306e\u5358\u8a9e\u306f\u3001\u901a\u5e38\u306eJavaScript\u30b3\u30fc\u30c9\u3067\u306f\u8b58\u5225\u5b50\u3068\u3057\u3066\u4f7f\u3048\u307e\u3059\u304c\u3001strict\u30e2\u30fc\u30c9\u306e\u5834\u5408\u306f\u4e88\u7d04\u8a9e\u3068\u3057\u3066\u6271\u308f\u308c\u8b58\u5225\u5b50\u306b\u306f\u4f7f\u3048\u307e\u305b\u3093\u3002<\/span><\/em><\/p>\n\n\n\n\n
implement<\/td>\nlet<\/td>\nprivate<\/td>\npublic<\/td>\nyield<\/td>\n<\/tr>\n
interface<\/td>\npackage<\/td>\nprotected<\/td>\nstatic<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

JavaScript \u306b\u306f\u3001\u305f\u304f\u3055\u3093\u306e\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u3084\u95a2\u6570\u304c\u3042\u3089\u304b\u3058\u3081\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u5b9a\u7fa9\u6e08\u307f\u306e\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u3084\u30b0\u30ed\u30fc\u30d0\u30eb\u95a2\u6570\u3068\u540c\u3058\u540d\u524d\u3092\u8b58\u5225\u5b50\u306b\u4f7f\u3046\u3053\u3068\u306f\u907f\u3051\u305f\u65b9\u304c\u7121\u96e3\u3067\u3059\u3002<\/span><\/em><\/p>\n\n\n\n\n\n\n\n\n
argument<\/td>\nencodeURI<\/td>\nInfinity<\/td>\nNumber<\/td>\nRegExp<\/td>\n<\/tr>\n
Array<\/td>\nencodeURIComponent<\/td>\nisFinite<\/td>\nObject<\/td>\nString<\/td>\n<\/tr>\n
Boolean<\/td>\nError<\/td>\nisNaN<\/td>\nparseFloat<\/td>\nSyntaxError<\/td>\n<\/tr>\n
Date<\/td>\neval<\/td>\nJSON<\/td>\nparseInt<\/td>\nTypeError<\/td>\n<\/tr>\n
decodeURI<\/td>\nEvalError<\/td>\nMath<\/td>\nRangeError<\/td>\nundefined<\/td>\n<\/tr>\n
decodeURIComponent<\/td>\nfunction<\/td>\nNaN<\/td>\nReferenceError<\/td>\nURIError<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

3.9 \u5909\u6570\u306e\u5ba3\u8a00<\/strong><\/p>\n

JavaScript \u3067\u5909\u6570\u306e\u5ba3\u8a00\u3092\u3059\u308b\u306b\u306f\u3001\u30ad\u30fc\u30ef\u30fc\u30c9 var \u3092\u4f7f\u3044\u307e\u3059\u3002<\/span><\/em><\/p>\n

var i;\r\nvar sum;<\/span><\/pre>\n
\u8907\u6570\u306e\u5909\u6570\u3092\u30ab\u30f3\u30de(,)\u3067\u533a\u5207\u3063\u3066\u5ba3\u8a00\u3059\u308b\u3053\u3068\u3082\u3067\u304d\u307e\u3059\u3002<\/span><\/em><\/p>\n
var i, sum;<\/span><\/pre>\n
for \u30eb\u30fc\u30d7\u3084for\/in \u30eb\u30fc\u30d7\u3067var \u6587\u3092\u8a18\u8ff0\u3059\u308b\u3053\u3068\u3067\u3001\u30eb\u30fc\u30d7\u306e\u4e00\u90e8\u3068\u3057\u3066\u30eb\u30fc\u30d7\u5909\u6570\u3092\u5ba3\u8a00\u3059\u308b\u3053\u3068\u3082\u3067\u304d\u307e\u3059\u3002<\/span><\/em><\/p>\n
for (var i = 0; i < 10; i++) {\r\n\u00a0 var sum += i;\r\n}\r\nreturn sum;<\/span><\/pre>\n
\u3082\u3057var \u6587\u3067\u5909\u6570\u306e\u521d\u671f\u5024\u3092\u8a2d\u5b9a\u3057\u306a\u304b\u3063\u305f\u5834\u5408\u306f\u3001\u5ba3\u8a00\u3055\u308c\u305f\u5909\u6570\u306f\u3001\u4f55\u304b\u5024\u304c\u4ee3\u5165\u3055\u308c\u308b\u307e\u3067 undefined(\u672a\u5b9a\u7fa9\u5024)\u306b\u306a\u308a\u307e\u3059\u3002<\/span><\/em><\/p>\n
3.9.1 \u5ba3\u8a00\u306e\u7e70\u308a\u8fd4\u3057\u3068\u7701\u7565<\/strong><\/p>\n
var \u6587\u3067\u5ba3\u8a00\u3055\u308c\u3066\u3044\u306a\u3044\u5909\u6570\u304b\u3089\u5024\u3092\u8aad\u307f\u3060\u3057\u305f\u5834\u5408\u306f\u3001\u30a8\u30e9\u30fc\u306b\u306a\u308a\u307e\u3059\u3002ECMAScript 5 \u306e strict \u30e2\u30fc\u30c9\u3067\u306f\u3001\u5ba3\u8a00\u3055\u308c\u3066\u3044\u306a\u3044\u5909\u6570\u306b\u5bfe\u3057\u3066\u5024\u3092\u4ee3\u5165\u3057\u3066\u3082\u30a8\u30e9\u30fc\u306b\u306a\u308a\u307e\u3059\u3002\u3057\u304b\u3057\u3001\u6b74\u53f2\u7684\u306b\u306f\u3001\u3064\u307e\u308a\u975e strict \u30e2\u30fc\u30c9\u3067\u306f\u3001\u5ba3\u8a00\u3055\u308c\u3066\u3044\u306a\u3044\u5909\u6570\u306b\u5bfe\u3057\u3066\u5024\u3092\u4ee3\u5165\u3057\u305f\u5834\u5408\u3001JavaScript \u306f\u30b0\u30ed\u30fc\u30d0\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u30d7\u30ed\u30d1\u30c6\u30a3\u3068\u3057\u3066\u5909\u6570\u3092\u4f5c\u6210\u3057\u307e\u3059\u3002\u305f\u3060\u3057\u3001\u5b8c\u5168\u306b\u540c\u3058\u3068\u3044\u3046\u308f\u3051\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002~(\u4e2d\u7565)~ \u3064\u307e\u308a\u3001\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u3092\u5ba3\u8a00\u3057\u306a\u304f\u3066\u3082\u554f\u984c\u306a\u3044\u3068\u3044\u3046\u3053\u3068\u3067\u3059\u3002\u305f\u3060\u3057\u3001\u3053\u306e\u3088\u3046\u306a\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u30b9\u30bf\u30a4\u30eb\u306f\u6c7a\u3057\u3066\u3088\u3044\u3082\u306e\u3068\u306f\u8a00\u3048\u307e\u305b\u3093\u3002\u5909\u6570\u306f var \u3092\u4f7f\u3063\u3066\u5ba3\u8a00\u3059\u308b\u3088\u3046\u306b\u3057\u3066\u304f\u3060\u3055\u3044\u3002<\/span><\/em><\/p>\n
3.10 \u5909\u6570\u306e\u30b9\u30b3\u30fc\u30d7<\/strong><\/p>\n
\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9\u4e2d\u306b\u304a\u3051\u308b\u5909\u6570\u306e\u6709\u52b9\u7bc4\u56f2\u3092\u30b9\u30b3\u30fc\u30d7<\/strong>\u3068\u3044\u3044\u307e\u3059\u3002\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570<\/strong>\u306e\u30b9\u30b3\u30fc\u30d7\u306f\u3001\u30d7\u30ed\u30b0\u30e9\u30e0\u5168\u4f53\u3067\u3059\u3002\u30ed\u30fc\u30ab\u30eb\u5909\u6570<\/strong>\u306e\u30b9\u30b3\u30fc\u30d7\u306f\u3001\u305d\u306e\u5909\u6570\u304c\u5ba3\u8a00\u3055\u308c\u305f\u95a2\u6570\u306e\u4e2d\u3060\u3051\u306b\u9650\u5b9a\u3055\u308c\u307e\u3059\u3002\u95a2\u6570\u306e\u4e2d\u306b\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u3068\u540c\u3058\u540d\u524d\u306e\u30ed\u30fc\u30ab\u30eb\u5909\u6570\u304c\u3042\u3063\u305f\u5834\u5408\u306f\u3001\u30ed\u30fc\u30ab\u30eb\u5909\u6570\u304c\u512a\u5148\u3055\u308c\u307e\u3059\u3002\u3064\u307e\u308a\u3001\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u3068\u540c\u3058\u540d\u524d\u3067\u30ed\u30fc\u30ab\u30eb\u5909\u6570\u3084\u4eee\u5f15\u6570\u3092\u5ba3\u8a00\u3059\u308b\u3068\u3001\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u304c\u96a0\u3055\u308c\u307e\u3059\u3002<\/span><\/em><\/p>\n
var scope =\"global\";\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ \u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u3092\u5ba3\u8a00\u3059\u308b\u3002\r\nfunction checkscope() {\r\n\u00a0 var scope = \"local\";\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ \u540c\u3058\u540d\u524d\u3067\u30ed\u30fc\u30ab\u30eb\u5909\u6570\u3092\u5ba3\u8a00\u3059\u308b\u3002\r\n\u00a0 return scope;\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ \u30ed\u30fc\u30ab\u30eb\u5909\u6570\u306e\u5024\u304c\u8fd4\u3055\u308c\u308b\u3002\r\n}\r\ncheckscope()\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ => \"local\"<\/span><\/pre>\n
scope = \"global\";\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\/\/ var \u6587\u3092\u7701\u7565\u3057\u3066\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u3092\u5ba3\u8a00\u3059\u308b\u3002\r\nfunction checkscope2() {\r\n\u00a0 scope = \"local\";\u00a0\u00a0 \/\/ \u3042\u308c\uff01\u3053\u308c\u306f\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u3092\u5909\u66f4\u3057\u305f\u3053\u3068\u306b\u306a\u308b\u3002\r\n\u00a0 myscope = \"local\"; \/\/ \u4ee3\u5165\u3067\u65b0\u305f\u306a\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u304c\u6697\u9ed9\u7684\u306b\u5ba3\u8a00\u3002\u00a0\u00a0\u00a0\u00a0\u00a0 \r\n\u00a0 return { scope, myscope }\u00a0\u00a0\u00a0 \/\/ \uff12\u3064\u306e\u5024\u3092\u8fd4\u3059\u3002\r\n}\r\ncheckscope2()\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ => {\"local\",\"local\"}\r\nscope\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ => \"local\": \u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\u304c\u5909\u66f4\u3055\u308c\u305f\u3002\r\nmyscope\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \/\/ => \"local\": \u30b0\u30ed\u30fc\u30d0\u30eb\u306a\u540d\u524d\u7a7a\u9593\u306b\u8ffd\u52a0\u3055\u308c\u305f\u3002\r\n<\/span><\/pre>\n
4.13 \u95a2\u6570\u306e\u5b9a\u7fa9\u65b9\u6cd5\uff08\u5ba3\u8a00\u3001\u5f0f\u3001\u3082\u3057\u304f\u306f\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\uff09<\/strong><\/p>\n
\/\/ \u95a2\u6570\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\uff1a\u6700\u5f8c\u306e\u30d1\u30e9\u30e1\u30fc\u30bf\u306b\u306f\u95a2\u6570\u306e\u30ed\u30b8\u30c3\u30af\uff08\u95a2\u6570\u672c\u4f53\uff09\u304c\u5165\u308b<\/span><\/em><\/p>\n
var addConstructor = new Function('x',\u00a0 'y', 'return x + y');<\/span><\/pre>\n
\/\/ \u95a2\u6570\u5ba3\u8a00\uff08function \u6587\uff09<\/span><\/em><\/p>\n
function addStatement(x, y) {\r\n\u00a0 return x + y;\r\n}<\/span><\/pre>\n
\/\/ \u95a2\u6570\u5f0f<\/span><\/em><\/p>\n
var addExpression = function(x, y) {\r\n\u00a0 return x + y;\r\n};<\/span><\/pre>\n
\u6b21\u306e\u4f8b\u3067\u306f\u3001foo \u30d7\u30ed\u30d1\u30c6\u30a3\u3092\u30b0\u30ed\u30fc\u30d0\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306b\u683c\u7d0d\u3057\u3001\u7570\u306a\u308b\u30b9\u30b3\u30fc\u30d7\u304b\u3089foo \u30d7\u30ed\u30d1\u30c6\u30a3\u306b\u30a2\u30af\u30bb\u30b9\u3057\u307e\u3059\u3002<\/span><\/em><\/p>\n
var foo = 'bar';\u00a0 \/\/ foo \u306f\u30b0\u30ed\u30fc\u30d0\u30eb\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u76f4\u4e0b\u306b\u683c\u7d0d\u3055\u308c\u305f\u30b0\u30ed\u30fc\u30d0\u30eb\u5909\u6570\r\nvar myApp = function() {\u00a0 \/\/ \u95a2\u6570\u306f\u30b9\u30b3\u30fc\u30d7\u3092\u4f5c\u308b\u3053\u3068\u3092\u601d\u3044\u51fa\u3057\u3066\r\n\u00a0 var run = function() {\r\n\u00a0\u00a0\u00a0 alert(foo);\u00a0 \/\/ \u51fa\u529b: 'bar'\r\n}();\r\n}\r\nmyApp();<\/span><\/pre>\n","protected":false},"excerpt":{"rendered":"
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