{"id":12778,"date":"2023-11-28T23:06:01","date_gmt":"2023-11-28T15:06:01","guid":{"rendered":"https:\/\/wx.kaifamiao.info\/?p=12778"},"modified":"2023-11-29T21:46:34","modified_gmt":"2023-11-29T13:46:34","slug":"javascript-zhong-wei-shen-me-ci-dai-maobj-someprop","status":"publish","type":"post","link":"http:\/\/wx.kaifamiao.info\/index.php\/2023\/11\/28\/javascript-zhong-wei-shen-me-ci-dai-maobj-someprop\/","title":{"rendered":"JavaScript \u4e2d\u4e3a\u4ec0\u4e48\u6b64\u4ee3\u7801 obj.someprop.x \u4f1a\u5f15\u53d1\u9519\u8bef\uff1f"},"content":{"rendered":"<p>\u5728 JavaScript \u4e2d\uff0c\u5982\u679c <code>obj.someprop<\/code> \u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u503c\uff0c\u5e76\u4e14\u5c1d\u8bd5\u5bf9\u8be5\u503c\u4f7f\u7528\u70b9\u64cd\u4f5c\u7b26\uff08<code>.<\/code>\uff09\u8bbf\u95ee\u5176\u5c5e\u6027 <code>x<\/code>\uff0c\u800c\u8be5\u503c\u4e0d\u662f\u5bf9\u8c61\uff08\u4f8b\u5982\u662f undefined \u6216\u8005 null\uff09\uff0c\u5c31\u4f1a\u5bfc\u81f4 TypeError \u9519\u8bef\uff0c\u56e0\u4e3a\u53ea\u6709\u5bf9\u8c61\u624d\u80fd\u591f\u6709\u5c5e\u6027\u3002\u8fd9\u79cd\u9519\u8bef\u901a\u5e38\u79f0\u4e3a &quot;Cannot read property &#8216;x&#8217; of undefined&quot; \u6216 &quot;Cannot read property &#8216;x&#8217; of null&quot;\uff0c\u53d6\u51b3\u4e8e <code>obj.someprop<\/code> \u7684\u503c\u662f undefined \u8fd8\u662f null\u3002<\/p>\n<p>\u4f8b\u5982\uff1a<\/p>\n<pre><code class=\"language-javascript\">let obj = {\n    someprop: null\n};\n\n\/\/ \u4ee5\u4e0b\u4ee3\u7801\u4f1a\u5bfc\u81f4 TypeError \u9519\u8bef\uff0c\u56e0\u4e3a null \u6ca1\u6709\u5c5e\u6027 'x'\nlet value = obj.someprop.x;\n<\/code><\/pre>\n<p>\u8fd9\u79cd\u9519\u8bef\u901a\u5e38\u53d1\u751f\u5728\u8bd5\u56fe\u8bbf\u95ee\u672a\u5b9a\u4e49\u6216 null \u7684\u5c5e\u6027\u65f6\uff0c\u56e0\u4e3a\u5728 JavaScript \u4e2d\uff0c\u53ea\u6709\u5bf9\u8c61\u624d\u80fd\u62e5\u6709\u5c5e\u6027\uff0c\u5c1d\u8bd5\u5bf9\u975e\u5bf9\u8c61\u7684\u503c\u4f7f\u7528\u70b9\u64cd\u4f5c\u7b26\u8bbf\u95ee\u5c5e\u6027\u4f1a\u5bfc\u81f4\u9519\u8bef\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5728 JavaScript \u4e2d\uff0c\u5982\u679c obj.someprop \u8fd4\u56de\u7684\u662f\u4e00\u4e2a\u503c\uff0c\u5e76\u4e14\u5c1d\u8bd5\u5bf9\u8be5\u503c\u4f7f\u7528\u70b9\u64cd\u4f5c\u7b26\uff08.\uff09 [&hellip;]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[115],"tags":[],"class_list":["post-12778","post","type-post","status-publish","format-standard","hentry","category-javascript"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/12778","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=12778"}],"version-history":[{"count":2,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/12778\/revisions"}],"predecessor-version":[{"id":13519,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/12778\/revisions\/13519"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=12778"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=12778"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=12778"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}