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undefined和null区别 #17

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Liqiuyue9597 opened this issue Aug 9, 2020 · 3 comments
Open

undefined和null区别 #17

Liqiuyue9597 opened this issue Aug 9, 2020 · 3 comments
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JavaScript 商汤科技 字节跳动

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@Liqiuyue9597
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@Liqiuyue9597
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null更像C++语言中的空指针，将变量赋值为null表示这是一个引用类型，只是暂时没有值。
undefined表示当前变量声明了但未赋值。

@ChinaWuhua
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个人理解：
null：已定义，但没有值
undefined：未定义

@liboliang01
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个人理解：
undefined：已声明还未赋值
null：值为空

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@ChinaWuhua @Liqiuyue9597 @liboliang01