{"id":52564,"date":"2024-12-03T14:38:34","date_gmt":"2024-12-03T06:38:34","guid":{"rendered":"https:\/\/fwq.ai\/blog\/52564\/"},"modified":"2024-12-03T14:38:34","modified_gmt":"2024-12-03T06:38:34","slug":"data-map-%e7%9a%84%e4%bd%bf%e7%94%a8%ef%bc%9a%e7%82%ab%e6%8a%80%e8%bf%98%e6%98%af%e5%ae%9e%e7%94%a8%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/52564\/","title":{"rendered":"data?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f"},"content":{"rendered":"<p><b><\/b>     <\/p>\n<h1>data?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f<\/h1>\n<p><span style=\"color: #222222;, sans-serif;background-color: #FFFFFF\">\u5404\u4f4d\u5c0f\u4f19\u4f34\u4eec\uff0c\u5927\u5bb6\u597d\u5440\uff01\u770b\u770b\u4eca\u5929\u6211\u53c8\u7ed9\u5404\u4f4d\u5e26\u6765\u4e86\u4ec0\u4e48\u6587\u7ae0\uff1f\u672c\u6587\u6807\u9898<span style=\"color: #222222;, sans-serif;background-color: #FFFFFF\">\u662f<\/span><span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\">\u300adata?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f\u300b<\/span>\uff0c\u5f88\u660e\u663e\u662f\u5173\u4e8e<span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\">\u6587\u7ae0<\/span>\u7684\u6587\u7ae0\u54c8\u54c8\u54c8\uff0c\u5176\u4e2d\u5185\u5bb9\u4e3b\u8981\u4f1a\u6d89\u53ca\u5230<span style=\"color: #FF6600;, Helvetica, Arial, sans-serif;font-size: 14px;background-color: #FFFFFF\"><\/span>\u7b49\u7b49\uff0c\u5982\u679c\u80fd\u5e2e\u5230\u4f60\uff0c\u89c9\u5f97\u5f88\u4e0d\u9519\u7684\u8bdd\uff0c\u6b22\u8fce\u5404\u4f4d\u591a\u591a\u70b9\u8bc4\u548c\u5206\u4eab\uff01<\/span><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241121\/1732181796673eff24a9a47.jpg\" class=\"aligncenter\" title=\"data?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f\u63d2\u56fe\" alt=\"data?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f\u63d2\u56fe\" \/><\/p>\n<p><strong>data?.map\u7684\u4f7f\u7528<\/strong><\/p>\n<p>\u5728\u793a\u4f8b\u4ee3\u7801\u4e2d\uff0c\u6211\u4eec\u4f7f\u7528 data?.map \u8868\u8fbe\u5f0f\u6765\u786e\u4fdd\u5728 data \u4e3a\u7a7a\u65f6\u4e0d\u4f1a\u629b\u51fa\u9519\u8bef\u3002\u6b64\u8868\u8fbe\u5f0f\u4f7f\u7528\u53ef\u9009\u94fe\u64cd\u4f5c\u7b26 ?.\uff0c\u5b83\u4f1a\u68c0\u67e5 data \u662f\u5426\u4e3a null \u6216 undefined\uff0c\u5982\u679c\u662f\u5219\u8fd4\u56de undefined\uff0c\u5426\u5219\u8fd4\u56de data.map \u7684\u7ed3\u679c\u3002<\/p>\n<p>\u8fd9\u79cd\u65b9\u6cd5\u5bf9\u4e8e\u5904\u7406\u53ef\u80fd\u4e3a\u7a7a\u7684\u5bf9\u8c61\u6216\u53d8\u91cf\u975e\u5e38\u6709\u7528\uff0c\u56e0\u4e3a\u5b83\u53ef\u4ee5\u9632\u6b62\u4ee3\u7801\u5728\u9047\u5230\u7a7a\u503c\u65f6\u5d29\u6e83\u3002<\/p>\n<p><strong>\u662f\u70ab\u6280\u5417\uff1f<\/strong><\/p>\n<p>\u662f\u5426\u5c06 data?.map \u89c6\u4f5c\u70ab\u6280\u53d6\u51b3\u4e8e\u4e2a\u4eba\u7684\u89c2\u70b9\u3002\u4e00\u4e9b\u5f00\u53d1\u4eba\u5458\u53ef\u80fd\u8ba4\u4e3a\u5b83\u662f\u4e00\u4e2a\u6e05\u6670\u4e14\u7b80\u6d01\u7684\u8bed\u6cd5\u7cd6\uff0c\u800c\u53e6\u4e00\u4e9b\u5f00\u53d1\u4eba\u5458\u5219\u53ef\u80fd\u8ba4\u4e3a\u5b83\u662f\u4e0d\u5fc5\u8981\u7684\u590d\u6742\u5316\u3002<\/p>\n<p>\u4e0e\u76f4\u63a5\u4f7f\u7528 data.map \u76f8\u6bd4\uff0cdata?.map \u5177\u6709\u4ee5\u4e0b\u4f18\u70b9\uff1a<\/p>\n<ul>\n<li>\u66f4\u5065\u58ee\uff0c\u53ef\u4ee5\u9632\u6b62\u7a7a\u6307\u9488\u5f02\u5e38<\/li>\n<li>\u4ee3\u7801\u7b80\u6d01\uff0c\u907f\u514d\u4e86\u5197\u957f\u7684\u4e09\u5143\u8fd0\u7b97\u7b26\u6216 if \u8bed\u53e5<\/li>\n<\/ul>\n<p>\u6700\u7ec8\uff0c\u662f\u5426\u4f7f\u7528 data?.map \u7531\u5f00\u53d1\u4eba\u5458\u6839\u636e\u5176\u4e2a\u4eba\u559c\u597d\u548c\u9879\u76ee\u8981\u6c42\u51b3\u5b9a\u3002\u5728\u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u8fd9\u662f\u4e00\u4e2a\u6709\u7528\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u548c\u5065\u58ee\u6027\u3002<\/p>\n<p><strong>\u5176\u4ed6\u6709\u7528\u7684 JS \u8bed\u6cd5<\/strong><\/p>\n<p>\u9664\u4e86 data?.map \u4e4b\u5916\uff0cJS \u4e2d\u8fd8\u6709\u8bb8\u591a\u5176\u4ed6\u6709\u7528\u7684\u8bed\u6cd5\uff0c\u4f8b\u5982\uff1a<\/p>\n<ul>\n<li>\u53ef\u9009\u94fe\u8fd0\u7b97\u7b26\uff08?.\uff09<\/li>\n<li>\u7a7a\u503c\u903b\u8f91\u8d4b\u503c\u7b26\uff08??=\uff09<\/li>\n<li>\u79fb\u4f4d\u8fd0\u7b97\u7b26\uff08&lt;&lt;, &gt;&gt;, &lt;&lt;=, &gt;&gt;=\uff09<\/li>\n<li>\u6269\u5c55\u8fd0\u7b97\u7b26\uff08&#8230;\uff09<\/li>\n<li>\u89e3\u6784\u8d4b\u503c<\/li>\n<\/ul>\n<p>\u4eca\u5929\u5173\u4e8e\u300adata?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f\u300b\u7684\u5185\u5bb9\u5c31\u4ecb\u7ecd\u5230\u8fd9\u91cc\u4e86\uff0c\u662f\u4e0d\u662f\u5b66\u8d77\u6765\u4e00\u76ee\u4e86\u7136\uff01\u60f3\u8981\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u7684\u5185\u5bb9\u8bf7\u5173\u6ce8\u7c73\u4e91\u516c\u4f17\u53f7\uff01<\/p>\n<dl>\n<dt><\/dt>\n<dd>\n   \u7535\u8111\u56fe\u6807\u4fee\u6539\u65b9\u6cd5\u53ca\u6b65\u9aa4\n <\/dd>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>data?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f \u5404\u4f4d\u5c0f\u4f19\u4f34\u4eec\uff0c\u5927\u5bb6\u597d\u5440\uff01\u770b\u770b\u4eca\u5929\u6211\u53c8\u7ed9\u5404\u4f4d\u5e26\u6765\u4e86\u4ec0\u4e48\u6587\u7ae0\uff1f\u672c\u6587\u6807\u9898\u662f\u300adata?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f\u300b\uff0c\u5f88\u660e\u663e\u662f\u5173\u4e8e\u6587\u7ae0\u7684\u6587\u7ae0\u54c8\u54c8\u54c8\uff0c\u5176\u4e2d\u5185\u5bb9\u4e3b\u8981\u4f1a\u6d89\u53ca\u5230\u7b49\u7b49\uff0c\u5982\u679c\u80fd\u5e2e\u5230\u4f60\uff0c\u89c9\u5f97\u5f88\u4e0d\u9519\u7684\u8bdd\uff0c\u6b22\u8fce\u5404\u4f4d\u591a\u591a\u70b9\u8bc4\u548c\u5206\u4eab\uff01 data?.map\u7684\u4f7f\u7528 \u5728\u793a\u4f8b\u4ee3\u7801\u4e2d\uff0c\u6211\u4eec\u4f7f\u7528 data?.map \u8868\u8fbe\u5f0f\u6765\u786e\u4fdd\u5728 data \u4e3a\u7a7a\u65f6\u4e0d\u4f1a\u629b\u51fa\u9519\u8bef\u3002\u6b64\u8868\u8fbe\u5f0f\u4f7f\u7528\u53ef\u9009\u94fe\u64cd\u4f5c\u7b26 ?.\uff0c\u5b83\u4f1a\u68c0\u67e5 data \u662f\u5426\u4e3a null \u6216 undefined\uff0c\u5982\u679c\u662f\u5219\u8fd4\u56de undefined\uff0c\u5426\u5219\u8fd4\u56de data.map \u7684\u7ed3\u679c\u3002 \u8fd9\u79cd\u65b9\u6cd5\u5bf9\u4e8e\u5904\u7406\u53ef\u80fd\u4e3a\u7a7a\u7684\u5bf9\u8c61\u6216\u53d8\u91cf\u975e\u5e38\u6709\u7528\uff0c\u56e0\u4e3a\u5b83\u53ef\u4ee5\u9632\u6b62\u4ee3\u7801\u5728\u9047\u5230\u7a7a\u503c\u65f6\u5d29\u6e83\u3002 \u662f\u70ab\u6280\u5417\uff1f \u662f\u5426\u5c06 data?.map \u89c6\u4f5c\u70ab\u6280\u53d6\u51b3\u4e8e\u4e2a\u4eba\u7684\u89c2\u70b9\u3002\u4e00\u4e9b\u5f00\u53d1\u4eba\u5458\u53ef\u80fd\u8ba4\u4e3a\u5b83\u662f\u4e00\u4e2a\u6e05\u6670\u4e14\u7b80\u6d01\u7684\u8bed\u6cd5\u7cd6\uff0c\u800c\u53e6\u4e00\u4e9b\u5f00\u53d1\u4eba\u5458\u5219\u53ef\u80fd\u8ba4\u4e3a\u5b83\u662f\u4e0d\u5fc5\u8981\u7684\u590d\u6742\u5316\u3002 \u4e0e\u76f4\u63a5\u4f7f\u7528 data.map \u76f8\u6bd4\uff0cdata?.map \u5177\u6709\u4ee5\u4e0b\u4f18\u70b9\uff1a \u66f4\u5065\u58ee\uff0c\u53ef\u4ee5\u9632\u6b62\u7a7a\u6307\u9488\u5f02\u5e38 \u4ee3\u7801\u7b80\u6d01\uff0c\u907f\u514d\u4e86\u5197\u957f\u7684\u4e09\u5143\u8fd0\u7b97\u7b26\u6216 if \u8bed\u53e5 \u6700\u7ec8\uff0c\u662f\u5426\u4f7f\u7528 data?.map \u7531\u5f00\u53d1\u4eba\u5458\u6839\u636e\u5176\u4e2a\u4eba\u559c\u597d\u548c\u9879\u76ee\u8981\u6c42\u51b3\u5b9a\u3002\u5728\u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u8fd9\u662f\u4e00\u4e2a\u6709\u7528\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u63d0\u9ad8\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u548c\u5065\u58ee\u6027\u3002 \u5176\u4ed6\u6709\u7528\u7684 JS \u8bed\u6cd5 \u9664\u4e86 data?.map \u4e4b\u5916\uff0cJS \u4e2d\u8fd8\u6709\u8bb8\u591a\u5176\u4ed6\u6709\u7528\u7684\u8bed\u6cd5\uff0c\u4f8b\u5982\uff1a \u53ef\u9009\u94fe\u8fd0\u7b97\u7b26\uff08?.\uff09 \u7a7a\u503c\u903b\u8f91\u8d4b\u503c\u7b26\uff08??=\uff09 \u79fb\u4f4d\u8fd0\u7b97\u7b26\uff08&lt;&lt;, &gt;&gt;, &lt;&lt;=, &gt;&gt;=\uff09 \u6269\u5c55\u8fd0\u7b97\u7b26\uff08&#8230;\uff09 \u89e3\u6784\u8d4b\u503c \u4eca\u5929\u5173\u4e8e\u300adata?.map \u7684\u4f7f\u7528\uff1a\u70ab\u6280\u8fd8\u662f\u5b9e\u7528\uff1f\u300b\u7684\u5185\u5bb9\u5c31\u4ecb\u7ecd\u5230\u8fd9\u91cc\u4e86\uff0c\u662f\u4e0d\u662f\u5b66\u8d77\u6765\u4e00\u76ee\u4e86\u7136\uff01\u60f3\u8981\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u7684\u5185\u5bb9\u8bf7\u5173\u6ce8\u7c73\u4e91\u516c\u4f17\u53f7\uff01 \u7535\u8111\u56fe\u6807\u4fee\u6539\u65b9\u6cd5\u53ca\u6b65\u9aa4<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-52564","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/52564","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=52564"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/52564\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=52564"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=52564"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=52564"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}