Comments (7)
没有10年脑血栓应该写不出这种代码
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答案
1 undefined
解析
条件判断为假的情况有:0,false,'',null,undefined,未定义对象。函数声明写在运算符中,其为true,但放在运算符中的函数声明在执行阶段是找不到的。另外,对未声明的变量执行typeOf不会报错,会返回undefined
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结果应该是NaN吧,1+undefined=NaN
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结果应该是NaN吧,1+undefined=NaN
typeof 返回的是字符串哦
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放在运算符中的函数声明在执行阶段是找不到的
理解这个意思,但是这种行为是写在规范里的么?找了一圈没找到,有没有什么出处?
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函数声明写在运算符中,其为true,但放在运算符中的函数声明在执行阶段是找不到的。
@Genzhen 不太理解这句话的意思。
我测试在严格模式下,chrome 执行结果为1function
。
个人理解,函数声明会被提升到所有代码执行前,所以在整个代码任何地方都能访问到f。
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