{"id":5372,"date":"2023-01-05T12:32:55","date_gmt":"2023-01-05T04:32:55","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=5372"},"modified":"2023-01-05T12:32:55","modified_gmt":"2023-01-05T04:32:55","slug":"%e4%ba%86%e8%a7%a3typescript%e4%b8%ad%e7%9a%84never%e9%a1%9e%e5%9e%8b%e5%8a%9f%e8%83%bd","status":"publish","type":"post","link":"https:\/\/badgameshow.com\/steven\/typescript\/%e4%ba%86%e8%a7%a3typescript%e4%b8%ad%e7%9a%84never%e9%a1%9e%e5%9e%8b%e5%8a%9f%e8%83%bd\/","title":{"rendered":"\u4e86\u89e3TypeScript\u4e2d\u7684never\u985e\u578b\u529f\u80fd"},"content":{"rendered":"

<\/p>\n

\u5982\u4f55\u5229\u7528 TypeScript “never”<\/h1>\n

TypeScript \u662f\u4e00\u7a2e JavaScript \u7684\u8d85\u96c6\uff0c\u5b83\u63d0\u4f9b\u4e86\u985e\u578b\u6aa2\u67e5\u548c\u5176\u4ed6\u529f\u80fd\uff0c\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u66f4\u5bb9\u6613\u5730\u958b\u767c\u51fa\u53ef\u9760\u7684\u7a0b\u5f0f\u78bc\u3002\u5728 TypeScript \u4e2d\uff0c\u6709\u4e00\u500b\u7279\u6b8a\u7684\u985e\u578b\u53eb\u505a “never”\uff0c\u5b83\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u66f4\u5bb9\u6613\u5730\u6aa2\u67e5\u7a0b\u5f0f\u78bc\u4e2d\u7684\u932f\u8aa4\uff0c\u4e26\u4e14\u66f4\u5bb9\u6613\u5730\u4fee\u5fa9\u5b83\u5011\u3002<\/p>\n

<\/p>\n

“Never” \u662f\u4e00\u7a2e\u7279\u6b8a\u7684 TypeScript \u985e\u578b\uff0c\u5b83\u8868\u793a\u4e00\u500b\u51fd\u5f0f\u6c38\u9060\u4e0d\u6703\u8fd4\u56de\u4efb\u4f55\u503c\u3002\u5b83\u53ef\u4ee5\u7528\u65bc\u6aa2\u67e5\u51fd\u5f0f\u662f\u5426\u6709\u6b63\u78ba\u7684\u8fd4\u56de\u503c\uff0c\u4ee5\u53ca\u6aa2\u67e5\u51fd\u5f0f\u662f\u5426\u6709\u6b63\u78ba\u7684\u53c3\u6578\u3002<\/p>\n

\u8209\u500b\u4f8b\u5b50\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u51fd\u5f0f\uff0c\u5b83\u63a5\u53d7\u4e00\u500b\u6578\u5b57\u53c3\u6578\uff0c\u4e26\u4e14\u8fd4\u56de\u4e00\u500b\u5b57\u4e32\uff1a<\/p>\n

\nfunction getStringFromNumber(num: number): string {\n  return num.toString();\n}\n<\/pre>\n
\u5728\u9019\u500b\u51fd\u5f0f\u4e2d\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528 “never” \u4f86\u6aa2\u67e5\u53c3\u6578\u662f\u5426\u6b63\u78ba\uff1a<\/p>\n
\nfunction getStringFromNumber(num: number | never): string {\n  if (typeof num !== 'number') {\n    throw new Error('num must be a number');\n  }\n  return num.toString();\n}\n<\/pre>\n
\u5728\u9019\u500b\u51fd\u5f0f\u4e2d\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528 “never” \u4f86\u6aa2\u67e5\u51fd\u5f0f\u662f\u5426\u6709\u6b63\u78ba\u7684\u8fd4\u56de\u503c\uff1a<\/p>\n
\nfunction getStringFromNumber(num: number): string | never {\n  if (typeof num !== 'number') {\n    throw new Error('num must be a number');\n  }\n  if (num < 0) {\n    throw new Error('num must be greater than or equal to 0');\n  }\n  return num.toString();\n}\n<\/pre>\n
\u9019\u6a23\uff0c\u6211\u5011\u5c31\u53ef\u4ee5\u78ba\u4fdd\u51fd\u5f0f\u53ea\u6703\u8fd4\u56de\u6b63\u78ba\u7684\u503c\uff0c\u800c\u4e0d\u6703\u8fd4\u56de\u932f\u8aa4\u7684\u503c\u3002<\/p>\n
\u53e6\u5916\uff0c\u6211\u5011\u9084\u53ef\u4ee5\u4f7f\u7528 \"never\" \u4f86\u6aa2\u67e5\u51fd\u5f0f\u662f\u5426\u6709\u6b63\u78ba\u7684\u53c3\u6578\uff1a<\/p>\n
\nfunction getStringFromNumber(num: number | never): string {\n  if (typeof num !== 'number') {\n    throw new Error('num must be a number');\n  }\n  return num.toString();\n}\n<\/pre>\n
\u9019\u6a23\uff0c\u6211\u5011\u5c31\u53ef\u4ee5\u78ba\u4fdd\u51fd\u5f0f\u53ea\u6703\u63a5\u53d7\u6b63\u78ba\u7684\u53c3\u6578\uff0c\u800c\u4e0d\u6703\u63a5\u53d7\u932f\u8aa4\u7684\u53c3\u6578\u3002<\/p>\n
\u7e3d\u7d50\u4f86\u8aaa\uff0cTypeScript \u7684 \"never\" \u985e\u578b\u53ef\u4ee5\u8b93\u958b\u767c\u8005\u66f4\u5bb9\u6613\u5730\u6aa2\u67e5\u7a0b\u5f0f\u78bc\u4e2d\u7684\u932f\u8aa4\uff0c\u4e26\u4e14\u66f4\u5bb9\u6613\u5730\u4fee\u5fa9\u5b83\u5011\u3002\u5b83\u53ef\u4ee5\u7528\u65bc\u6aa2\u67e5\u51fd\u5f0f\u662f\u5426\u6709\u6b63\u78ba\u7684\u8fd4\u56de\u503c\u548c\u53c3\u6578\uff0c\u4ee5\u53ca\u6aa2\u67e5\u51fd\u5f0f\u662f\u5426\u6709\u6b63\u78ba\u7684\u53c3\u6578\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u4e86\u89e3TypeScript\u4e2d\u7684never\u985e\u578b\uff0c\u5b83\u662f\u4e00\u7a2e\u7279\u6b8a\u7684\u985e\u578b\uff0c\u53ef\u4ee5\u7528\u65bc\u8868\u793a\u6c38\u4e0d\u5b58\u5728\u7684\u503c\u7684\u60c5\u6cc1\uff0c\u53ef\u4ee5\u5e6b\u52a9\u60a8\u66f4\u597d\u5730\u63a7\u5236\u7a0b\u5e8f\u7684\u884c\u70ba\uff0c\u4e26\u63d0\u9ad8\u4ee3\u78bc\u7684\u53ef\u8b80\u6027\u548c\u53ef\u7dad\u8b77\u6027\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-5372","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\/pcFK27-1oE","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/5372","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=5372"}],"version-history":[{"count":1,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/5372\/revisions"}],"predecessor-version":[{"id":5373,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/5372\/revisions\/5373"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=5372"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=5372"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=5372"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}