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📜  如何检查对象中是否存在键javascript代码示例

📅  最后修改于: 2022-03-11 15:03:14.188000             🧑  作者: Mango

代码示例6
!("key" in obj) // true if "key" doesn't exist in object
!"key" in obj   // ERROR!  Equivalent to "false in obj"