{"id":50,"date":"2020-10-30T20:22:42","date_gmt":"2020-10-30T12:22:42","guid":{"rendered":"http:\/\/qqiuklele.cn\/?p=50"},"modified":"2025-03-26T15:21:05","modified_gmt":"2025-03-26T07:21:05","slug":"%e4%ba%86%e8%a7%a3%e5%87%bd%e6%95%b0%e8%a1%a8%e8%be%be%e5%bc%8f%e4%b8%ad%e7%9a%84iife","status":"publish","type":"post","link":"https:\/\/qqiukulele.cn\/?p=50","title":{"rendered":"\u4e86\u89e3\u51fd\u6570\u8868\u8fbe\u5f0f\u4e2d\u7684IIFE"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">\u524d\u8a00<\/h2>\n\n\n\n<p>\u5728\u6211\u65ad\u65ad\u7eed\u7eed\u5730\u5b66\u4e60\u95ed\u5305\u7684\u65f6\u5019\uff0c\u771f\u7684\u662f\u597d\u50cf\u8d8a\u5b66\u8d8a\u7cca\u6d82\uff0c\u603b\u611f\u89c9\u4ec0\u4e48\u90fd\u662f\u95ed\u5305~\u5148\u8bf4\u8bf4\u6211\u4e4b\u524d\u8bb0\u4f4f\u7684\u6982\u5ff5\uff08\u4e00\u6bb5\u975e\u5e38\u751f\u786c\u7684\u6982\u5ff5\u3002\uff09\uff1a<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u95ed\u5305\u5141\u8bb8\u51fd\u6570\u8bbf\u95ee\u5e76\u64cd\u4f5c\u51fd\u6570\u5916\u90e8\u7684\u53d8\u91cf\u3002\u53ea\u8981\u53d8\u91cf\u6216\u51fd\u6570\u5b58\u5728\u4e8e\u58f0\u660e\u51fd\u6570\u65f6\u7684\u4f5c\u7528\u57df\u5185\uff0c\u95ed\u5305\u5373\u53ef\u4f7f\u51fd\u6570\u80fd\u591f\u8bbf\u95ee\u8fd9\u4e9b\u53d8\u91cf\u6216\u51fd\u6570\u3002<\/p>\n<\/blockquote>\n\n\n\n<p>\u5176\u5b9e\u771f\u7684\u7406\u89e3\u95ed\u5305\uff0c\u770b\u8fd9\u6bb5\u8bdd\u80af\u5b9a\u4f1a\u70b9\u5934\u8bf4\u5bf9\uff0c\u7136\u9e45\u6211\u7adf\u7136\u53ea\u8bb0\u4f4f\u4e86\u524d\u9762\u4e00\u53e5\u8bdd\uff0c\u5bfc\u81f4\u6211\u505a\u6628\u5929\u7684\u9762\u8bd5\u9898\u65f6\u89c9\u5f97\u4ee5\u4e0b\u5730\u51fd\u6570test\u662f\u4e2a\u95ed\u5305\uff0c\u76f4\u63a5\u5224\u65ad\u51fa\u9519~<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var test = 1;\n(function test() {    \n    test = 7;   \n    console.log(test); })(); \nconsole.log(test);\n<\/code><\/pre>\n\n\n\n<p>\u8fd9\u5f53\u7136\u4e0d\u662f\u95ed\u5305\uff0c\u6211\u4e5f\u662f\u540e\u6765\u624d\u77e5\u9053\u8fd9\u4e2a<strong>IIFE\uff08\u7acb\u5373\u8c03\u7528\u51fd\u6570\uff09<\/strong>\u4e5f\u662f<strong>\u51fd\u6570\u8868\u8fbe\u5f0f<\/strong>?\u3002\u6211\u771f\u7684\u6ca1\u8003\u8651\u8fc7\u5b83\u5c5e\u4e8e\u51fd\u6570\u8868\u8fbe\u5f0f\u8fd8\u662f\u51fd\u6570\u58f0\u660e\u3002\u77e5\u9053\u8fd9\u70b9\u540e\u6211\u628a\u4ee3\u7801\u8fd9\u6837\u4fee\u6539\u4e86\u4e00\u4e0b\uff0c\u6211\u8ba4\u4e3a\u63a7\u5236\u53f0\u6253\u5370\u76844\u4e2a\u7ed3\u679c\u90fd\u662f7\uff0c\u6bd5\u7adf\u90fd\u662f\u51fd\u6570\u8868\u8fbe\u5f0f\u3002\u4f46\u662f\u6211\u5374\u53d1\u73b0\u540c\u6837\u662f\u51fd\u6570\u8868\u8fbe\u5f0f\uff0c\u6253\u5370\u7684\u7ed3\u679c\u5b8c\u5168\u4e0d\u4e00\u6837\u5462\uff01\uff01\u4e3b\u8981\u662fIIFE\u90e8\u5206\u6253\u5370\u7684\u7ed3\u679c\u5b8c\u5168\u548c\u6211\u60f3\u7684\u4e0d\u4e00\u6837\u3002\u90a3<strong>IIFE\u5230\u5e95\u662f\u600e\u6837\u7684\u8fd0\u884c\u673a\u5236<\/strong>\uff0c\u5982\u6b64\u795e\u5947\uff1f<strong>\u5b83\u548c\u5e73\u65f6\u5e38\u89c1\u7684\u666e\u901a\u51fd\u6570\u8868\u8fbe\u5f0f\u6709\u4ec0\u4e48\u4e0d\u4e00\u6837\u7684\u5730\u65b9\uff1f\u4e3a\u4ec0\u4e48\u4e0d\u540c\u6837\u8f93\u51fa7\uff1f<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var test = 1;\n(function test() {  \n  test = 7;  \n  console.log(test); \/\/\u8fd9\u91cc\u6253\u5370\u7684\u4e0d\u662f7\n   })(); \nconsole.log(test);  \/\/\u8fd9\u91cc\u5f53\u7136\u4e5f\u4e0d\u662f7\ntest = function() {\n  test = 7;  \n  console.log(test); \n}\ntest()\nconsole.log(test);\n<\/code><\/pre>\n\n\n\n<figure class=\"wp-block-image size-full\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='http:\/\/qqiukulele.cn\/wp-content\/uploads\/2020\/10\/image.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" decoding=\"async\" width=\"243\" height=\"150\" data-original=\"http:\/\/qqiukulele.cn\/wp-content\/uploads\/2020\/10\/image.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" class=\"wp-image-472\"\/><\/div><\/figure>\n\n\n\n<p>\u6253\u5370\u7ed3\u679c<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">\u51fd\u6570\u58f0\u660e\u4e0e\u51fd\u6570\u8868\u8fbe\u5f0f\u4e4b\u95f4\u7684\u533a\u522b<\/h2>\n\n\n\n<p>\u5148\u4e00\u5c42\u5c42\u5730\u6162\u6162\u4e86\u89e3\uff0c\u9996\u5148\u8981\u77e5\u9053\u51fd\u6570\u58f0\u660e\u4e0e\u51fd\u6570\u8868\u8fbe\u5f0f\u4e4b\u95f4\u5730\u533a\u522b\u5728\u4e8e\uff1a<strong>\u51fd\u6570\u58f0\u660e\u7684\u51fd\u6570\u540d\u79f0\u4f1a\u88ab\u7ed1\u5b9a\u5728\u6240\u5728\u7684\u4f5c\u7528\u57df\u91cc\uff0c\u5728\u51fd\u6570\u58f0\u660e\u88ab\u5b9a\u4e49\u4e4b\u524d\uff0c\u5b83\u5c31\u53ef\u4ee5\u88ab\u8c03\u7528\u4e86\u3002\u51fd\u6570\u8868\u8fbe\u5f0f\u7684\u51fd\u6570\u540d\u79f0\u662f\u7ed1\u5b9a\u5728\u51fd\u6570\u8868\u8fbe\u5f0f\u81ea\u8eab\u7684\u51fd\u6570\u4e2d\u800c\u4e0d\u662f\u6240\u5728\u7684\u4f5c\u7528\u57df\u4e2d\u3002\u51fd\u6570\u8868\u8fbe\u5f0f\u662f\u5728\u4ee3\u7801\u6267\u884c\u5230\u8fbe\u65f6\u88ab\u521b\u5efa\uff0c\u5e76\u4e14\u4ec5\u4ece\u90a3\u4e00\u523b\u8d77\u53ef\u7528\u3002<\/strong><\/p>\n\n\n\n<p>\u6240\u4ee5\uff0c\u5728\u7b2c\u4e00\u6b21\u58f0\u660etest = function(){&#8230;}\u524d\u8c03\u7528test()\u51fd\u6570\u4e00\u5b9a\u4f1a\u62a5\u9519\u7684\u3002\uff08\u5c0f\u58f0\u63d0\u9192\u81ea\u5df1\uff1a\u4e0d\u662fundefined\uff0c\u5c31\u662f\u62a5\u9519\uff01\uff09\u56e0\u4e3a\u5728\u4f5c\u7528\u57df\u91cc\u5c31\u627e\u4e0d\u5230test\u3002<\/p>\n\n\n\n<p>\u540c\u6837\u7684\uff0c(function test() {&#8230;})\u4f5c\u4e3a\u51fd\u6570\u8868\u8fbe\u5f0f\u5c31\u610f\u5473\u7740test\u51fd\u6570\u540d\u79f0\u53ea\u80fd\u5728{&#8230;}\u91cc\u88ab\u8bbf\u95ee\u3002\u968f\u7740\u5b83\u7684\u7acb\u5373\u8c03\u7528\u5b8c\uff0c\u8fd9\u4e2a\u51fd\u6570\u7684test\u53d8\u91cf\u540d\u5c31\u4e0d\u4f1a\u4e5f\u4e0d\u80fd\u5728\u5916\u90e8\u4f5c\u7528\u57df\u51fa\u73b0\u4e86\uff0c\u6216\u8005\u8bf4\u5b83\u907f\u514d\u4e86\u6c61\u67d3\u5916\u90e8\u4f5c\u7528\u57df\u3002\u6211\u4eec\u53ef\u4ee5\u4fee\u6539\u4ee3\u7801\u770b\u770b\uff0c\u5148\u4e0d\u7ba1\u4e3a\u4ec0\u4e48\u7b2c\u4e00\u4e2atest\u4e0d\u662f7\uff0c\u81f3\u5c11\u660e\u767d\u51fd\u6570\u58f0\u660e\u4e0e\u51fd\u6570\u8868\u8fbe\u5f0f\u5206\u522b\u5c06\u5b83\u4eec\u7684\u540d\u79f0\u6807\u8bc6\u7b26\u7ed1\u5b9a\u54ea\u513f\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/\u90fd\u662f\u51fd\u6570\u8868\u8fbe\u5f0f~\n(function test() {  \n  test = 7;  \n  console.log(typeof test); \/\/function\n   })(); \n\n   function testB() {\n    testB = 7;  \n  console.log(typeof testB); \/\/nunber\n   }\n   testB()\n<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">IIFE\u5230\u5e95\u662f\u600e\u6837\u7684\u51fd\u6570\u8868\u8fbe\u5f0f<\/h2>\n\n\n\n<p>\u4f46\u662f\u73b0\u5728\u8fd8\u662f\u4f1a\u9677\u5165\u5f88\u5c34\u5c2c\u7684\u5c40\u9762\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>(function test() {  \n  test = 7;  \n  console.log( test); \n    \/\/\u0192 test() { test =7;console.log(test); \n     }\n   })(); \nvar test = function() {\n  test = 7;  \n  console.log(test); \/\/7\n}\ntest()\n<\/code><\/pre>\n\n\n\n<p>\u4e0d\u90fd\u662f\u51fd\u6570\u8868\u8fbe\u5f0f\uff0c\u4e3a\u4f55IIFE\u771f\u5c31\u90a3\u4e48\u7279\u7acb\u72ec\u884c\uff0c\u5979\u4e3a\u4ec0\u4e48\u4e0d\u7b49\u4e8e7\u2757\u5176\u5b9e\u5728\u4e00\u5f00\u59cb\u7684\u4ee3\u7801\u52a0\u5165\u4e00\u884c &#8220;use strict&#8221;; \u5c31\u77e5\u9053\u4e3a\u4ec0\u4e48\u4e86\u3002\u8fd9\u6bb5\u4ee3\u7801\u5728\u4e25\u683c\u6a21\u5f0f\u4e0b\u662f\u4f1a\u62a5\u9519\u7684\u3002\u62a5\u9519\u7684\u5185\u5bb9\u662f\uff1a<code>Uncaught TypeError: Assignment to constant variable.<\/code>   \u6709\u9053\u7ffb\u8bd1\u4e00\u4e0b\uff1a<em>\u672a\u6355\u83b7\u7c7b\u578b\u9519\u8bef:\u5bf9\u5e38\u91cf\u53d8\u91cf\u7684\u8d4b\u503c<\/em><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\"use strict\"; \/\/\u7acb\u9a6c\u62a5\u9519~~~\nvar test = 1;\n(function test() {  \n   test = 7;  \n   console.log(test); \n })(); \n<\/code><\/pre>\n\n\n\n<p>\u56e0\u4e3aIIFE\u7684\u51fd\u6570\u8868\u8fbe\u5f0f\u7684\u5f62\u5f0f\u5176\u5b9e\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>const test = function() {\n  console.log(test); \n}\ntest()\n<\/code><\/pre>\n\n\n\n<p>\u5e76\u4e0d\u662f\u6211\u8ba4\u4e3a\u7684\u628a\u8fd9\u4e2a\u51fd\u6570\u8d4b\u503c\u7ed9\u666e\u901a\u53d8\u91cf\uff0c\u4e8b\u5b9e\u662f\u5e94\u8be5<strong>\u8d4b\u503c\u7ed9\u5e38\u91cfconst<\/strong>\u3002\u6b63\u56e0\u4e3aIIFE\u7684\u8fd9\u4e00\u70b9\uff0c\u5bfc\u81f4\u7f16\u8bd1\u5668\u5728\u6267\u884c\u7684\u65f6\u5019\uff0c\u4f1a\u5ffd\u7565\u6389test = 7\u8fd9\u4e00\u53e5\u3002\u6240\u4ee5\u4e3a\u561b\u4e0d\u8f93\u51fa7\uff1f\u5c31\u56e0\u4e3a\u6211test\u662f\u5e38\u91cf\uff01\u8bd5\u4e00\u8bd5\u628a\u8fd9\u4e2atest\u51fd\u6570\u53d8\u6210\u81ea\u52a8\u6267\u884c\u7684\u533f\u540d\u51fd\u6570\uff0c\u4e5f\u5c31\u662f\u4e0d\u4f1a\u56e0\u6b64\u5b58\u5728test\u5e38\u91cf\uff0c\u8fd9\u4e0b\u51fd\u6570\u5185\u7684\u6253\u5370\u5c31\u53ef\u4ee5\u6b63\u5e38\u6253\u5370\u51fa7\u6765\u3002<\/p>\n\n\n\n<p>\u987a\u4fbf\u8865\u5145\u4e00\u4e0b\uff1a<em>ES6<\/em> \u7684\u6a21\u5757\u81ea\u52a8\u91c7\u7528<em>\u4e25\u683c\u6a21\u5f0f<\/em>\uff0c\u6240\u4ee5\u8d4b\u503c\u7ed9\u5e38\u91cf\u7684\u51fd\u6570\u91cc\u662f\u4e0d\u80fd\u518d\u628a\u51fd\u6570\u540d\u62ff\u51fa\u6765\u91cd\u65b0\u8d4b\u503c\u7684\uff0c\u4e0d\u7136\u4f1a\u62a5\u9519\u3002\u6240\u4ee5\u6211\u4e0a\u9762\u7684\u4ee3\u7801\u628atest = 7\u8fd9\u4e00\u884c\u5220\u9664\u4e86\u3002\u8fd9\u70b9\u548cIIFE\u5c31\u6709\u70b9\u4e0d\u540c\u4e86\u3002<\/p>\n\n\n\n<p class=\"has-text-color\" style=\"color:#220505\"> \u6240\u4ee5\u603b\u7ed3\u4e00\u4e0b\u6628\u5929\u505a\u7684\u8fd9\u9053\u9898:<strong>test\u51fd\u6570\u662f\u4e00\u4e2a\u51fd\u6570\u8868\u8fbe\u5f0f\uff0c\u4e0d\u53ef\u63d0\u5347\uff0c\u4e14\u8fd9\u4e2a\u7acb\u5373\u8c03\u7528\u51fd\u6570\u662f\u8d4b\u503c\u7ed9\u5e38\u91cf\u3002<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u51fd\u6570\u58f0\u660e\u7684\u51fd\u6570\u540d\u79f0\u4f1a\u88ab\u7ed1\u5b9a\u5728\u6240\u5728\u7684\u4f5c\u7528\u57df\u91cc\uff0c\u5728\u51fd\u6570\u58f0\u660e\u88ab\u5b9a\u4e49\u4e4b\u524d\uff0c\u5b83\u5c31\u53ef\u4ee5\u88ab\u8c03\u7528\u4e86\u3002\u51fd\u6570\u8868\u8fbe\u5f0f\u7684\u51fd\u6570\u540d\u79f0\u662f\u7ed1\u5b9a\u5728\u51fd\u6570\u8868\u8fbe\u5f0f\u81ea\u8eab\u7684\u51fd\u6570\u4e2d\u800c\u4e0d\u662f\u6240\u5728\u7684\u4f5c\u7528\u57df\u4e2d\u3002\u51fd\u6570\u8868\u8fbe\u5f0f\u662f\u5728\u4ee3\u7801\u6267\u884c\u5230\u8fbe\u65f6\u88ab\u521b\u5efa\uff0c\u5e76\u4e14\u4ec5\u4ece\u90a3\u4e00\u523b\u8d77\u53ef\u7528\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21],"tags":[19],"class_list":["post-50","post","type-post","status-publish","format-standard","hentry","category-21","tag-js"],"_links":{"self":[{"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=\/wp\/v2\/posts\/50","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=50"}],"version-history":[{"count":3,"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=\/wp\/v2\/posts\/50\/revisions"}],"predecessor-version":[{"id":474,"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=\/wp\/v2\/posts\/50\/revisions\/474"}],"wp:attachment":[{"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=50"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=50"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qqiukulele.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=50"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}