理解JavaScript Truthy和Falsy [英] Understanding JavaScript Truthy and Falsy
问题描述
有人可以使用以下示例数据解释JavaScript Truthy和Falsy。我已阅读其他主题但仍感到困惑。
Can someone please explain JavaScript Truthy and Falsy, using the below sample data. I have read other threads but still confused.
var a = 0;
var a = 10 == 5;
var a = 1;
var a = -1;
据我了解,我相信 var a = 1;
是唯一的truthy,其余的都是假的 - 这是正确的吗?
From my understanding, I believe that var a = 1;
is the only truthy and the rest are falsy - is this correct?
推荐答案
根据我的理解,我相信var a = 1;是唯一的truthy,其余的是假的 - 这是正确的吗?
From my understanding, I believe that var a = 1; is the only truthy and the rest are falsy’s - is this correct?
否。
var a = 0;
var a = 0;
数字零是 falsy 。但请注意,字符串零0
是真实的。
Number zero is falsy. However, note that the string zero "0"
is truthy.
var a = 10 == 5;
var a = 10 == 5;
这与 var a =(10 == 5)相同);
,所以这是 falsy 。
var a = 1;
var a = 1;
var a = -1;
var a = -1;
任何非零包含负数的数字是 truthy 。
Any non-zero number including negative numbers is truthy.
引自 HTML
在JavaScript中, truthy值是在布尔上下文中计算时转换为true的值。所有值都是真实的,除非它们被定义为假的(即,除了
false
,0
,,
null
,undefined
和NaN
)。
JavaScript中的虚假值列表: 来自MDN
-
false
-
null
-
undefined
-
0
-
NaN
-
''
-
document.all
false
null
undefined
0
NaN
''
document.all
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