{"id":4840,"date":"2023-01-05T10:45:14","date_gmt":"2023-01-05T02:45:14","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=4840"},"modified":"2023-01-05T10:45:14","modified_gmt":"2023-01-05T02:45:14","slug":"%e5%ad%b8%e7%bf%92%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8typescript%e7%b1%bb%e5%9e%8b%e6%96%ad%e8%a8%80%e4%be%86%e6%8f%90%e5%8d%87%e7%a8%8b%e5%bc%8f%e7%a2%bc%e5%93%81%e8%b3%aa","status":"publish","type":"post","link":"https:\/\/badgameshow.com\/steven\/typescript\/%e5%ad%b8%e7%bf%92%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8typescript%e7%b1%bb%e5%9e%8b%e6%96%ad%e8%a8%80%e4%be%86%e6%8f%90%e5%8d%87%e7%a8%8b%e5%bc%8f%e7%a2%bc%e5%93%81%e8%b3%aa\/","title":{"rendered":"\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528TypeScript\u7c7b\u578b\u65ad\u8a00\u4f86\u63d0\u5347\u7a0b\u5f0f\u78bc\u54c1\u8cea"},"content":{"rendered":"<p><meta name=\"keywords\" content=\"TypeScript, TypeScript \u7c7b\u578b\u65ad\u8a00, Type Assertion\"><\/p>\n<h1>\u4ec0\u9ebc\u662f TypeScript \u7c7b\u578b\u65ad\u8a00(Type Assertion)<\/h1>\n<p>TypeScript \u7c7b\u578b\u65ad\u8a00(Type Assertion)\u662f\u4e00\u7a2e\u6280\u8853\uff0c\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u5728\u4e0d\u6539\u8b8a\u8b8a\u6578\u578b\u5225\u7684\u60c5\u6cc1\u4e0b\uff0c\u5c0d\u8b8a\u6578\u578b\u5225\u9032\u884c\u65b7\u8a00\u3002\u5b83\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u5728\u7a0b\u5f0f\u78bc\u4e2d\u6307\u5b9a\u8b8a\u6578\u7684\u578b\u5225\uff0c\u800c\u4e0d\u662f\u8b93 TypeScript \u81ea\u52d5\u63a8\u65b7\u3002<\/p>\n<p>TypeScript \u7c7b\u578b\u65ad\u8a00\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u5728\u7a0b\u5f0f\u78bc\u4e2d\u66f4\u52a0\u7cbe\u78ba\u5730\u6307\u5b9a\u8b8a\u6578\u7684\u578b\u5225\uff0c\u4ee5\u53ca\u66f4\u52a0\u6e05\u695a\u5730\u8868\u9054\u958b\u767c\u8005\u7684\u610f\u5716\u3002<\/p>\n<h2>TypeScript \u7c7b\u578b\u65ad\u8a00\u7684\u8a9e\u6cd5<\/h2>\n<p>TypeScript \u7c7b\u578b\u65ad\u8a00\u7684\u8a9e\u6cd5\u6709\u5169\u7a2e\uff1a\u300c\u5c16\u62ec\u865f\u300d\u8a9e\u6cd5\u548c\u300cas\u300d\u8a9e\u6cd5\u3002<\/p>\n<h3>\u5c16\u62ec\u865f\u8a9e\u6cd5<\/h3>\n<p>\u5c16\u62ec\u865f\u8a9e\u6cd5\u662f TypeScript \u7c7b\u578b\u65ad\u8a00\u7684\u6700\u5e38\u7528\u8a9e\u6cd5\uff0c\u5b83\u7684\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code class=\"line-numbers\">&lt;Type&gt;variable\n<\/code><\/pre>\n<p>\u5176\u4e2d\uff0c<code>&lt;Type&gt;<\/code> \u662f\u6307\u5b9a\u8b8a\u6578\u7684\u578b\u5225\uff0c<code>variable<\/code> \u662f\u6307\u5b9a\u7684\u8b8a\u6578\u3002<\/p>\n<p>\u8209\u500b\u4f8b\u5b50\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u8b8a\u6578 <code>myName<\/code>\uff0c\u5b83\u7684\u578b\u5225\u662f <code>string<\/code>\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528\u5c16\u62ec\u865f\u8a9e\u6cd5\u5c0d\u5b83\u9032\u884c\u65b7\u8a00\uff1a<\/p>\n<pre><code class=\"line-numbers\">&lt;string&gt;myName\n<\/code><\/pre>\n<h3>as \u8a9e\u6cd5<\/h3>\n<p>as \u8a9e\u6cd5\u662f TypeScript \u7c7b\u578b\u65ad\u8a00\u7684\u53e6\u4e00\u7a2e\u8a9e\u6cd5\uff0c\u5b83\u7684\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code class=\"line-numbers\">variable as Type\n<\/code><\/pre>\n<p>\u5176\u4e2d\uff0c<code>variable<\/code> \u662f\u6307\u5b9a\u7684\u8b8a\u6578\uff0c<code>Type<\/code> \u662f\u6307\u5b9a\u8b8a\u6578\u7684\u578b\u5225\u3002<\/p>\n<p>\u8209\u500b\u4f8b\u5b50\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u8b8a\u6578 <code>myName<\/code>\uff0c\u5b83\u7684\u578b\u5225\u662f <code>string<\/code>\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528 as \u8a9e\u6cd5\u5c0d\u5b83\u9032\u884c\u65b7\u8a00\uff1a<\/p>\n<pre><code class=\"line-numbers\">myName as string\n<\/code><\/pre>\n<h2>TypeScript \u7c7b\u578b\u65ad\u8a00\u7684\u7bc4\u4f8b<\/h2>\n<p>\u73fe\u5728\u6211\u5011\u4f86\u770b\u4e00\u500b TypeScript \u7c7b\u578b\u65ad\u8a00\u7684\u7bc4\u4f8b\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u8b8a\u6578 <code>myName<\/code>\uff0c\u5b83\u7684\u578b\u5225\u662f <code>any<\/code>\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528\u5c16\u62ec\u865f\u8a9e\u6cd5\u5c0d\u5b83\u9032\u884c\u65b7\u8a00\uff1a<\/p>\n<p>&#8220;`<\/p>\n<pre class=\"brush: typescript\">\nlet myName: any = \"John\";\nlet myNameLength = (<string>myName).length;\nconsole.log(myNameLength); \/\/ 4\n<\/pre>\n<p>\u5728\u4e0a\u9762\u7684\u7bc4\u4f8b\u4e2d\uff0c\u6211\u5011\u4f7f\u7528\u5c16\u62ec\u865f\u8a9e\u6cd5\u5c0d <code>myName<\/code> \u9032\u884c\u65b7\u8a00\uff0c\u6307\u5b9a\u5b83\u7684\u578b\u5225\u70ba <code>string<\/code>\uff0c\u7136\u5f8c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528 <code>myName<\/code> \u7684 <code>length<\/code> \u5c6c\u6027\u4f86\u53d6\u5f97\u5b57\u4e32\u7684\u9577\u5ea6\u3002<\/p>\n<h2>\u7e3d\u7d50<\/h2>\n<p>TypeScript \u7c7b\u578b\u65ad\u8a00(Type Assertion)\u662f\u4e00\u7a2e\u6280\u8853\uff0c\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u5728\u4e0d\u6539\u8b8a\u8b8a\u6578\u578b\u5225\u7684\u60c5\u6cc1\u4e0b\uff0c\u5c0d\u8b8a\u6578\u578b\u5225\u9032\u884c\u65b7\u8a00\u3002\u5b83\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u5728\u7a0b\u5f0f\u78bc\u4e2d\u6307\u5b9a\u8b8a\u6578\u7684\u578b\u5225\uff0c\u800c\u4e0d\u662f\u8b93 TypeScript \u81ea\u52d5\u63a8\u65b7\u3002TypeScript \u7c7b\u578b\u65ad\u8a00\u7684\u8a9e\u6cd5\u6709\u5169\u7a2e\uff1a\u300c\u5c16\u62ec\u865f\u300d\u8a9e\u6cd5\u548c\u300cas\u300d\u8a9e\u6cd5\u3002<\/p>\n<p><!--more--><\/p>\n<p>TypeScript \u7c7b\u578b\u65ad\u8a00\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u5728\u7a0b\u5f0f\u78bc\u4e2d\u66f4\u52a0\u7cbe\u78ba\u5730\u6307\u5b9a\u8b8a\u6578\u7684\u578b\u5225\uff0c\u4ee5\u53ca\u66f4\u52a0\u6e05\u695a\u5730\u8868\u9054\u958b\u767c\u8005\u7684\u610f\u5716\u3002\u5b83\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u66f4\u52a0\u8f15\u9b06\u5730\u64b0\u5beb\u7a0b\u5f0f\u78bc\uff0c\u4e26\u4e14\u53ef\u4ee5\u6e1b\u5c11\u7a0b\u5f0f\u78bc\u51fa\u932f\u7684\u6a5f\u7387\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6587\u7ae0\u6458\u8981\uff1aTypeScript\u7c7b\u578b\u65ad\u8a00\u662f\u4e00\u7a2e\u6280\u8853\uff0c\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u66f4\u597d\u5730\u63a7\u5236\u7a0b\u5f0f\u78bc\u7684\u884c\u70ba\uff0c\u63d0\u9ad8\u7a0b\u5f0f\u78bc\u7684\u54c1\u8cea\uff0c\u4e26\u6e1b\u5c11\u51fa\u932f\u7684\u6a5f\u6703\u3002\u672c\u6587\u5c07\u4ecb\u7d39TypeScript\u7c7b\u578b\u65ad\u8a00\u7684\u57fa\u672c\u6982\u5ff5\uff0c\u4ee5\u53ca\u5982\u4f55\u4f7f\u7528\u5b83\u4f86\u63d0\u5347\u7a0b\u5f0f\u78bc\u54c1\u8cea\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[187],"tags":[186],"class_list":["post-4840","post","type-post","status-publish","format-standard","hentry","category-typescript","tag-typescript"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack-related-posts":[],"jetpack_shortlink":"https:\/\/wp.me\/pcFK27-1g4","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4840","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/comments?post=4840"}],"version-history":[{"count":1,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4840\/revisions"}],"predecessor-version":[{"id":4841,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4840\/revisions\/4841"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=4840"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=4840"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=4840"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}