{"id":6117,"date":"2020-05-07T19:41:06","date_gmt":"2020-05-07T11:41:06","guid":{"rendered":"https:\/\/www.lilichao.com\/?p=6117"},"modified":"2022-05-14T19:44:08","modified_gmt":"2022-05-14T11:44:08","slug":"%e4%bd%9c%e7%94%a8%e5%9f%9f%e9%93%be","status":"publish","type":"post","link":"https:\/\/lilichao.com\/?p=6117","title":{"rendered":"\u4f5c\u7528\u57df\u94fe"},"content":{"rendered":"\n

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\"\"
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let a = 10;\nlet b = 'hello';<\/code><\/pre>\n\n\n\n
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let a = 10;\nlet b = 'hello';\n{\n    let c = 33\n}<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u4ee3\u7801\u4e2d\u591a\u4e86\u4e00\u4e2a\u4ee3\u7801\u5757\uff0c\u4ee3\u7801\u5757\u4f1a\u521b\u5efa\u51fa\u5757\u4f5c\u7528\u57df\uff0c\u5757\u4f5c\u7528\u57df\u4f4d\u4e8e\u5168\u5c40\u4f5c\u7528\u57df\u5185\u90e8\uff0c\u6240\u4ee5\u5728\u5757\u4f5c\u7528\u57df\u4e2d\u4f1a\u5bf9\u5176\u5916\u90e8\u7684\u5168\u5c40\u4f5c\u7528\u57df\u8fdb\u884c\u5b58\u50a8\u3002<\/p>\n\n\n\n
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\"\"
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\"\"
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\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
\/\/\u5168\u5c40\u4f5c\u7528\u57df<\/code>\nlet a = 10;\nlet b = 'hello';\n{ \/\/\u5916\u5c42\u4ee3\u7801\u5757\n     let c = 33;\n     { \/\/\u5185\u5c42\u4ee3\u7801\u5757\n         let d = 44;\n     }\n}<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u4e2d\uff0c\u4ee5\u5185\u5c42\u4ee3\u7801\u5757\u4e3a\u4f8b\uff0c\u5047\u8bbe\u6211\u4eec\u8981\u5728\u5185\u5c42\u4ee3\u7801\u5757\u4e2d\u901a\u8fc7console.log(d)<\/code>\u6765\u8bbf\u95ee\u53d8\u91cfd\uff0c\u6b64\u65f6\u6d4f\u89c8\u5668\u4f1a\u5148\u5728\u5f53\u524d\u7684\u5757\u4f5c\u7528\u57df\u4e2d\u5bfb\u627e\uff0c\u5982\u679c\u627e\u5230\u4e86\u76f4\u63a5\u8fd4\u56ded\u7684\u503c\u3002\u5982\u679c\u6ca1\u6709\u627e\u5230\uff0c\u5219\u53bb\u5230\u5916\u5c42\u4ee3\u7801\u5757\u6240\u5728\u7684\u4f5c\u7528\u57df\u4e2d\u5bfb\u627e\uff0c\u627e\u5230\u5219\u4f7f\u7528\uff0c\u6ca1\u6709\u627e\u5230\u5219\u53bb\u5916\u5c42\u7684\u5168\u5c40\u4f5c\u7528\u57df\u4e2d\u5bfb\u627e\uff0c\u627e\u5230\u4e86\u5219\u4f7f\u7528\uff0c\u6ca1\u627e\u5230\u5219\u53bb\u5168\u5c40\u5bf9\u8c61\u4e2d\u5bfb\u627e\uff0c\u627e\u5230\u4e86\u4f7f\u7528\uff0c\u5982\u679c\u4f9d\u7136\u6ca1\u6709\u627e\u5230\u5219\u62a5\u9519\u3002<\/p>\n\n\n\n
\"\"
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\u51fd\u6570\u4f5c\u7528\u57df<\/h2>\n\n\n\n
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{
    let a = 10;
}<\/code><\/pre>\n\n\n\n
\u5757\u4f5c\u7528\u57df\u4f1a\u5728\u5757\u5f00\u59cb\u6267\u884c\u65f6\u521b\u5efa\uff0c\u6267\u884c\u7ed3\u675f\u540e\u9500\u6bc1\u3002\u6362\u53e5\u8bdd\u8bf4\u5728\u8fdb\u5165\u5de6\u5927\u62ec\u53f7{\u65f6\u5757\u4f5c\u7528\u57df\u5c31\u521b\u5efa\u4e86\uff0c\u79bb\u5f00\u53f3\u5927\u62ec\u53f7}\u65f6\u5c31\u9500\u6bc1\u4e86\u3002<\/p>\n\n\n\n
function fn(){
    let a = 33;
    let b = 'hello';
}<\/code><\/pre>\n\n\n\n
\u51fd\u6570\u4f5c\u7528\u57df\u4e0d\u592a\u4e00\u6837\uff0c\u50cf\u4e0a\u4f8b\u4e2d\u7684\u4ee3\u7801\u5e76\u4e0d\u4f1a\u521b\u5efa\u51fd\u6570\u4f5c\u7528\u57df\u3002\u51fd\u6570\u4f5c\u7528\u57df\u53ea\u4f1a\u5728\u51fd\u6570\u8c03\u7528\u65f6\u624d\u4f1a\u521b\u5efa\uff0c\u58f0\u660e\u521b\u5efa\u51fd\u6570\u5e76\u4e0d\u4f1a\u4ea7\u751f\u65b0\u7684\u4f5c\u7528\u57df\u3002\u8981\u4ea7\u751f\u51fd\u6570\u4f5c\u7528\u57df\u5fc5\u987b\u5bf9\u51fd\u6570\u8fdb\u884c\u8c03\u7528\u3002<\/p>\n\n\n\n
function fn(){<\/code>\n    let a = 33;<\/code>\n    let b = 'hello';<\/code>\n}<\/code>\nfn();<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u4e2d\u8c03\u7528fn()\u51fd\u6570\uff0c\u6b64\u65f6\u5c31\u4ea7\u751f\u4e86\u51fd\u6570\u4f5c\u7528\u57df\u5728\u51fd\u6570\u8c03\u7528\u65f6\uff0c\u4f5c\u7528\u57df\u521b\u5efa\uff0c\u8c03\u7528\u5b8c\u6bd5\u4f5c\u7528\u57df\u6d88\u5931\uff0c\u5e76\u4e14\u6bcf\u6b21\u8c03\u7528\u51fd\u6570\u90fd\u4f1a\u521b\u5efa\u4e00\u4e2a\u5168\u65b0\u7684\u4f5c\u7528\u57df\u3002\u4f8b\u5982\u8c03\u7528fn()\u51fd\u657010\u6b21\uff0c\u5c31\u4f1a\u521b\u5efa10\u4e2a\u4f5c\u7528\u57df\uff0c\u5e76\u4e1410\u4e2a\u4f5c\u7528\u57df\u4e4b\u95f4\u662f\u76f8\u4e92\u72ec\u7acb\u7684\uff0c\u4e92\u4e0d\u5f71\u54cd\u3002<\/p>\n\n\n\n
let a = 10;\nlet b = 'hello';\n \nfunction <\/code>fn<\/code><\/em>() {\n    let a = 22;\n    console.log(a); <\/code>\/\/ 22<\/code><\/em>\n    console.log(b); <\/code>\/\/ 'hello'<\/code><\/em>\n    console.log(c); <\/code>\/\/ \u62a5\u9519\n<\/code><\/em>}\n \n<\/code>fn<\/code><\/em>()<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u4e2d\uff0cfn\u662f\u4e00\u4e2a\u5168\u5c40\u51fd\u6570\uff0c\u5728\u51fd\u6570\u5185\u90e8\u6253\u5370\u4e86\u53d8\u91cfa\u548cb\uff0ca\u548cb\u7684\u503c\u5206\u522b\u662f\u591a\u5c11\u5462\uff1ffn\u662f\u5168\u5c40\u51fd\u6570\uff0c\u5b83\u7684\u4f5c\u7528\u57df\u662f\u8fd9\u6837\u4e00\u4e2a\u7ed3\u6784\uff1a<\/p>\n\n\n\n
\u51fd\u6570\u4f5c\u7528\u57df\uff08fn\uff09\u27a1\ufe0f \u5168\u5c40\u4f5c\u7528\u57df \u27a1\ufe0f \u5168\u5c40\u5bf9\u8c61\u3002<\/p>\n\n\n\n
\u8bbf\u95ee\u53d8\u91cfa\u65f6\uff0c\u4f1a\u5148\u5728\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u5bfb\u627e\uff0c\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u5b9a\u4e49\u4e86a\uff0c\u6240\u4ee5\u76f4\u63a5    \u8fd4\u56dea\u7684\u503c\uff0c\u537322\u3002<\/p>\n\n\n\n
\u8bbf\u95ee\u53d8\u91cfb\u65f6\uff0c\u5728\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u6ca1\u6709\u53d8\u91cfb\uff0c\u6240\u4ee5\u4f1a\u53bb\u4e0a\u4e00\u7ea7\u5168\u5c40\u4f5c\u7528\u57df\u4e2d\u5bfb\u627e\uff0c\u5168\u5c40\u4e2d\u6709\u53d8\u91cfb\uff0c\u76f4\u63a5\u8fd4\u56de\u5168\u5c40\u4e2d\u7684\u53d8\u91cfb\u7684\u503c\uff0c\u5373’hello’\u3002<\/p>\n\n\n\n
\u8bbf\u95ee\u53d8\u91cfc\u65f6\uff0c\u4f9d\u7136\u5728\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u627ec\uff0c\u6ca1\u6709\u3002\u518d\u53bb\u4e0a\u4e00\u7ea7\u5168\u5c40\u4f5c\u7528\u57df\u4e2d\u627e\uff0c\u6ca1\u6709\u3002\u6700\u540e\u53bb\u5168\u5c40\u5bf9\u8c61window\u4e2d\u5bfb\u627e\uff0c\u4f9d\u7136\u6ca1\u6709\uff0c\u6ca1\u8f99\u4e86\uff0c\u6700\u540e\u62a5\u9519\uff01 <\/p>\n\n\n\n
\u5982\u679c\u4ee3\u7801\u662f\u8fd9\u6837\u7684\u5462\uff1f<\/p>\n\n\n\n
let a = 10;\nlet b = 'hello';\n \nfunction <\/code>fn<\/code><\/em>(a, b, c) {\n    console.log(a); <\/code>\/\/ undefined<\/code><\/em>\n    console.log(b); <\/code>\/\/ undefined<\/code><\/em>\n    console.log(c); <\/code>\/\/ undefined\n<\/code><\/em>}\n \n<\/code>fn<\/code><\/em>()<\/code><\/pre>\n\n\n\n
\u4e0a\u8ff0\u6848\u4f8b\u4e2d\uff0c\u4e3afn\u6307\u5b9a\u4e86\u4e09\u4e2a\u5f62\u53c2a\u3001b\u548cc\u3002\u5b9a\u4e49\u5f62\u53c2\u76f8\u5f53\u4e8e\u5728\u51fd\u6570\u4e2d\u58f0\u660e\u4e86\u53d8\u91cf\uff0c\u867d\u7136\u6ca1\u6709\u4f20\u9012\u5b9e\u53c2\u4f46\u662f\u53d8\u91cf\u4e5f\u786e\u5b9e\u662f\u5b58\u5728\u7684\u53ea\u4e0d\u8fc7\u503c\u662fundefined\u3002\u6240\u4ee5\u6253\u5370a\u3001b\u3001c\u65f6\uff0c\u4e09\u4e2a\u503c\u90fd\u662fundefined\u3002\u603b\u4e4b\u8bb0\u4f4f\u4e86\uff0c\u5f62\u53c2\u5373\u53d8\u91cf\u3002<\/p>\n\n\n\n
\u73b0\u5728\uff0c\u51fd\u6570\u5728\u5168\u5c40\u4e2d\u5b9a\u4e49\uff0c\u4e5f\u5728\u5168\u5c40\u4e2d\u8c03\u7528\uff0c\u6240\u4ee5\u5bf9\u4e8e\u51fd\u6570\u6765\u8bf4\u5b83\u7684\u5916\u90e8\u4f5c\u7528\u57df\u5c31\u662f\u5168\u5c40\u4f5c\u7528\u57df\uff0c\u6240\u4ee5\u5bfb\u627e\u53d8\u91cf\u65f6\uff0c\u987a\u5e8f\u662f\u5148\u627e\u81ea\u5df1\u518d\u627e\u5168\u5c40\uff0c\u5982\u679c\u4fee\u6539\u4ee3\u7801\u7684\u7ed3\u6784\u4f1a\u662f\u4e00\u4e2a\u4ec0\u4e48\u6837\u5b50\u7684\u60c5\u51b5\u5462\uff1f<\/p>\n\n\n\n
let a = 10;\nlet b = 'hello';\n \nfunction <\/code>fn<\/code><\/em>() {\n    console.log(a); \/\/10\n    console.log(b); \/\/'hello'\n}\n \n{\n    let a = 100\n    let b = '\u4f60\u597d'\n    <\/code>fn<\/code><\/em>()\n}<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u4e2d\uff0c\u51fd\u6570\u7684\u8c03\u7528\u662f\u5728\u4e00\u4e2a\u4ee3\u7801\u5757\u4e2d\u8fdb\u884c\u7684\uff0c\u5728\u4ee3\u7801\u5757\u4e2d\u6709\u4e24\u4e2a\u5c40\u90e8\u53d8\u91cfa\u548cb\uff0c\u5728\u5168\u5c40\u4e2d\u4e5f\u6709\u4e24\u4e2a\u5168\u5c40\u53d8\u91cfa\u548cb\uff0c\u5728fn\u51fd\u6570\u4e2d\u8bbf\u95ee\u4e86\u4e24\u4e2a\u53d8\u91cf\uff0c\u95ee\u6b64\u65f6fn\u4e2d\u6253\u5370\u7684a\u548cb\u7684\u503c\u662f\u591a\u5c11\u5462\uff1f\u662f\u5168\u5c40\u7684a\u548cb\uff0c\u8fd8\u662f\u5757\u4f5c\u7528\u57df\u4e2d\u7684\u5c40\u90e8\u53d8\u91cfa\u548cb\u5462\uff1f<\/p>\n\n\n\n
\u5373\u4f7f\u7ed3\u6784\u5728\u600e\u4e48\u8c03\u6574\uff0c\u4f60\u9700\u8981\u8bb0\u4f4f\u53ea\u8981\u662f\u627e\u53d8\u91cf\u5c31\u662f\u6cbf\u7740\u4f5c\u7528\u57df\u94fe\u53bb\u5bfb\u627e\u3002\u8fd9\u91cc\u5728\u51fd\u6570\u5185\u90e8\u8bbf\u95ee\u4e86a\u548cb\uff0c\u9996\u5148\u8fd8\u662f\u5728\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u5bfb\u627e\uff0c\u6ca1\u6709\u3002\u63a5\u7740\u53bb\u5916\u5c42\u4f5c\u7528\u57df\u4e2d\u5bfb\u627e\uff0c\u73b0\u5728\u7684\u95ee\u9898\u662f\u5916\u5c42\u4f5c\u7528\u57df\u662f\u8c01\uff1f\u5168\u5c40\u4f5c\u7528\u57df\u8fd8\u662f\u5757\u4f5c\u7528\u57df\uff1f\u5982\u679c\u662f\u5168\u5c40\u4f5c\u7528\u57df\uff0c\u90a3\u4e48a\u7684\u503c\u5e94\u8be5\u662f10\uff0cb\u7684\u503c\u5e94\u8be5\u662f’hello’\u3002\u5982\u679c\u662f\u5757\u4f5c\u7528\u57df\uff0ca\u7684\u503c\u5e94\u8be5\u662f100\uff0cb\u7684\u503c\u5e94\u8be5\u662f’\u4f60\u597d’\u3002<\/p>\n\n\n\n
\u6240\u4ee5\u8fd9\u4e2a\u95ee\u9898\u7684\u5173\u952e\u5728\u4e8e\uff0c\u51fd\u6570\u4f5c\u7528\u57df\u7684\u5916\u5c42\u4f5c\u7528\u57df\u5230\u5e95\u662f\u8c01\uff1f<\/p>\n\n\n\n
\u51fd\u6570\u7684\u5916\u5c42\u4f5c\u7528\u57df\u7531\u51fd\u6570\u7684\u5b9a\u4e49\u4f4d\u7f6e\u51b3\u5b9a\uff01<\/p>\n\n\n\n
\u8bb0\u4f4f\u8fd9\u53e5\u8bdd\uff0c\u51fd\u6570\u7684\u5916\u5c42\u4f5c\u7528\u57df\u548c\u51fd\u6570\u7684\u8c03\u7528\u4f4d\u7f6e\u65e0\u5173\uff0c\u5b8c\u5168\u6709\u51fd\u6570\u5b9a\u4e49\u7684\u4f4d\u7f6e\u51b3\u5b9a\uff0c\u51fd\u6570\u5b9a\u4e49\u5728\u5168\u5c40\u4e2d\uff0c\u51fd\u6570\u4f5c\u7528\u57df\u7684\u5916\u5c42\u4f5c\u7528\u57df\u5c31\u662f\u5168\u5c40\u4f5c\u7528\u57df\u3002\u51fd\u6570\u5b9a\u4e49\u5728\u5757\u4e2d\uff0c\u51fd\u6570\u7684\u5916\u5c42\u4f5c\u7528\u57df\u5c31\u662f\u5757\u4f5c\u7528\u57df\u3002<\/p>\n\n\n\n
\u4e0a\u4f8b\u4e2d\uff0c\u51fd\u6570\u5b9a\u4e49\u5728\u4e86\u5168\u5c40\u4e2d\uff0c\u6240\u6709\u5b83\u7684\u5916\u5c42\u4f5c\u7528\u57df\u5c31\u662f\u5168\u5c40\u4f5c\u7528\u57df\uff0c\u6240\u4ee5\u8fd9\u662fa\u548cb\u7684\u503c\u5c31\u662f\u5168\u5c40\u4f5c\u7528\u57df\u4e2d\u7684a\u548cb\uff0c\u537310\u548c’hello’\u3002<\/p>\n\n\n\n
\"\"
Local\u51fd\u6570\u4f5c\u7528\u57df\uff0c\u5916\u5c42\u4e3aScript\u5168\u5c40\u4f5c\u7528\u57df<\/figcaption><\/figure><\/div>\n\n\n\n
\u5982\u679c\u628a\u51fd\u6570\u5b9a\u4e49\u5728\u4ee3\u7801\u5757\u4e2d\u5462\uff1f<\/p>\n\n\n\n
let a = 10;\nlet b = 'hello';\n \n{\n    let a = 100\n    let b = '\u4f60\u597d'<\/code>\n    function <\/code>fn<\/code><\/em>() {\n        console.log(a); \/\/100\n        console.log(b); \/\/'\u4f60\u597d'\n    }\n    \n}<\/code>\nfn<\/code><\/em>()<\/code><\/pre>\n\n\n\n
\u6b64\u65f6\u5728\u4ee3\u7801\u5757\u4e2d\u5b9a\u4e49\u51fd\u6570\uff0c\u5728\u5168\u5c40\u4f5c\u7528\u57df\u4e2d\u8c03\u7528\u51fd\u6570\uff08\u5728\u4ee3\u7801\u5757\u901a\u8fc7\u51fd\u6570\u58f0\u660e\u521b\u5efa\u7684\u51fd\u6570\u4e5f\u662f\u5168\u5c40\u51fd\u6570\uff09\u3002\u51fd\u6570\u5b9a\u4e49\u5728\u4e86\u4ee3\u7801\u5757\u4e2d\uff0c\u90a3\u4e48\u5b83\u7684\u5916\u5c42\u4f5c\u7528\u57df\u5c31\u662f\u5757\u4f5c\u7528\u57df\uff0c\u6240\u4ee5\u8fd9\u65f6\u7684\u4f5c\u7528\u57df\u5173\u7cfb\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n\n\n\n
\u51fd\u6570\u4f5c\u7528\u57df \u27a1\ufe0f \u5757\u4f5c\u7528\u57df \u27a1\ufe0f \u5168\u5c40\u4f5c\u7528\u57df \u27a1\ufe0f \u5168\u5c40\u5bf9\u8c61<\/p>\n\n\n\n
\u5f53\u5728\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u627e\u4e0d\u5230\u53d8\u91cfa\u548cb\u65f6\uff0c\u5b83\u4f1a\u53bb\u5757\u4f5c\u7528\u57df\u4e2d\u5bfb\u627e\uff0c\u6240\u4ee5\u4e0a\u8fb9\u7684\u4f8b\u5b50\u4e2d\uff0ca\u7684\u503c\u662f100\uff0cb\u7684\u503c\u662f’\u4f60\u597d’\u3002<\/p>\n\n\n\n
\"\"
Local\u51fd\u6570\u4f5c\u7528\u57df\uff0c\u5916\u5c42\u4e3aBlock\u5168\u5c40\u4f5c\u7528\u57df<\/figcaption><\/figure><\/div>\n","protected":false},"excerpt":{"rendered":"
\u6bcf\u4e00\u4e2a\u72ec\u7acb\u7684\u4f5c\u7528\u57df\uff0c\u90fd\u4f1a\u6709\u4e00\u4e2a\u53d8\u91cf\u5bf9\u8c61\uff08variable object\uff09\u7528\u4e8e\u5b58\u50a8\u5176\u4f5c\u7528\u57df\u4e2d\u6240\u6709\u7684\u53d8\u91cf\u3002\u4f46\u662f\u81ea\u4ece […]<\/p>\n","protected":false},"author":1,"featured_media":6125,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[241],"tags":[200,250,234],"_links":{"self":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6117"}],"collection":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6117"}],"version-history":[{"count":2,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6117\/revisions"}],"predecessor-version":[{"id":6128,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6117\/revisions\/6128"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/media\/6125"}],"wp:attachment":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6117"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6117"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6117"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}