{"id":3177,"date":"2024-11-10T14:06:43","date_gmt":"2024-11-10T06:06:43","guid":{"rendered":"https:\/\/fwq.ai\/blog\/3177\/"},"modified":"2024-11-10T14:06:43","modified_gmt":"2024-11-10T06:06:43","slug":"js%e5%a6%82%e4%bd%95%e5%88%a4%e6%96%ad%e7%a9%ba%e5%af%b9%e8%b1%a1%e4%b8%ba%e7%a9%ba","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/3177\/","title":{"rendered":"js\u5982\u4f55\u5224\u65ad\u7a7a\u5bf9\u8c61\u4e3a\u7a7a"},"content":{"rendered":"<blockquote><p>\n  \u5728 javascript \u4e2d\uff0c\u5224\u65ad\u7a7a\u5bf9\u8c61\u662f\u5426\u4e3a\u7a7a\u7684\u65b9\u6cd5\u6709\u4e24\u79cd\uff1aobject.keys() \u65b9\u6cd5\uff1a\u5224\u65ad\u5bf9\u8c61\u5c5e\u6027\u952e\u6570\u7ec4\u957f\u5ea6\u662f\u5426\u4e3a 0\u3002for&#8230;in \u5faa\u73af\uff1a\u5224\u65ad\u5faa\u73af\u662f\u5426\u6267\u884c\u8fc7\u4efb\u4f55\u8fed\u4ee3\u3002\n<\/p><\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/202411\/08\/2024110806161518875.jpg\" class=\"aligncenter\" title=\"js\u5982\u4f55\u5224\u65ad\u7a7a\u5bf9\u8c61\u4e3a\u7a7a\u63d2\u56fe\" alt=\"js\u5982\u4f55\u5224\u65ad\u7a7a\u5bf9\u8c61\u4e3a\u7a7a\u63d2\u56fe\" \/><\/p>\n<p><strong>JS \u4e2d\u5224\u65ad\u7a7a\u5bf9\u8c61\u662f\u5426\u4e3a\u7a7a<\/strong><\/p>\n<p>\u7a7a\u5bf9\u8c61\u662f\u6307\u6ca1\u6709\u5305\u542b\u4efb\u4f55\u5c5e\u6027\u7684 JavaScript \u5bf9\u8c61\u3002\u786e\u5b9a\u7a7a\u5bf9\u8c61\u662f\u5426\u4e3a\u7a7a\u7684\u65b9\u6cd5\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li>\n<p><strong>Object.keys() \u65b9\u6cd5\uff1a<\/strong><\/p>\n<ul>\n<li>\u8be5\u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2a\uff0c\u5176\u4e2d\u5305\u542b\u5bf9\u8c61\u4e2d\u6240\u6709\u5c5e\u6027\u7684\u952e\u3002<\/li>\n<li>\u5982\u679c Object.keys(obj).length \u7b49\u4e8e 0\uff0c\u5219\u5bf9\u8c61\u4e3a\u7a7a\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\n<p><strong>for&#8230;in \u5faa\u73af\uff1a<\/strong><\/p>\n<ul>\n<li>\u4f7f\u7528 for&#8230;in \u5faa\u73af\u904d\u5386\u5bf9\u8c61\u7684\u5c5e\u6027\u3002<\/li>\n<li>\u5982\u679c\u5faa\u73af\u6ca1\u6709\u6267\u884c\u4efb\u4f55\u8fed\u4ee3\uff0c\u5219\u5bf9\u8c61\u4e3a\u7a7a\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>\u793a\u4f8b\u4ee3\u7801\uff1a<\/p>\n<pre>\/\/ \u4f7f\u7528 Object.keys() \u65b9\u6cd5\nconst obj = {};\nconst isObjEmpty = Object.keys(obj).length === 0;\n\n\/\/ \u4f7f\u7528 for...in \u5faa\u73af\nconst obj2 = {};\nlet isObj2Empty = true;\nfor (const key in obj2) {\n  isObj2Empty = false;\n  break;\n}<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p>\u4ee5\u4e0a\u4e24\u79cd\u65b9\u6cd5\u90fd\u53ef\u4ee5\u6709\u6548\u5730\u5224\u65ad\u7a7a\u5bf9\u8c61\u662f\u5426\u4e3a\u7a7a\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662fjs\u5982\u4f55\u5224\u65ad\u7a7a\u5bf9\u8c61\u4e3a\u7a7a\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5728 javascript \u4e2d\uff0c\u5224\u65ad\u7a7a\u5bf9\u8c61\u662f\u5426\u4e3a\u7a7a\u7684\u65b9\u6cd5\u6709\u4e24\u79cd\uff1aobject.keys() \u65b9\u6cd5\uff1a\u5224\u65ad\u5bf9\u8c61\u5c5e\u6027\u952e\u6570\u7ec4\u957f\u5ea6\u662f\u5426\u4e3a 0\u3002for&#8230;in \u5faa\u73af\uff1a\u5224\u65ad\u5faa\u73af\u662f\u5426\u6267\u884c\u8fc7\u4efb\u4f55\u8fed\u4ee3\u3002 JS \u4e2d\u5224\u65ad\u7a7a\u5bf9\u8c61\u662f\u5426\u4e3a\u7a7a \u7a7a\u5bf9\u8c61\u662f\u6307\u6ca1\u6709\u5305\u542b\u4efb\u4f55\u5c5e\u6027\u7684 JavaScript \u5bf9\u8c61\u3002\u786e\u5b9a\u7a7a\u5bf9\u8c61\u662f\u5426\u4e3a\u7a7a\u7684\u65b9\u6cd5\u5982\u4e0b\uff1a Object.keys() \u65b9\u6cd5\uff1a \u8be5\u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2a\uff0c\u5176\u4e2d\u5305\u542b\u5bf9\u8c61\u4e2d\u6240\u6709\u5c5e\u6027\u7684\u952e\u3002 \u5982\u679c Object.keys(obj).length \u7b49\u4e8e 0\uff0c\u5219\u5bf9\u8c61\u4e3a\u7a7a\u3002 for&#8230;in \u5faa\u73af\uff1a \u4f7f\u7528 for&#8230;in \u5faa\u73af\u904d\u5386\u5bf9\u8c61\u7684\u5c5e\u6027\u3002 \u5982\u679c\u5faa\u73af\u6ca1\u6709\u6267\u884c\u4efb\u4f55\u8fed\u4ee3\uff0c\u5219\u5bf9\u8c61\u4e3a\u7a7a\u3002 \u793a\u4f8b\u4ee3\u7801\uff1a \/\/ \u4f7f\u7528 Object.keys() \u65b9\u6cd5 const obj = {}; 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