50 lines
1.5 KiB
Markdown
50 lines
1.5 KiB
Markdown
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---
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title: Number isFinite
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localeTitle: 数字是有限的
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---
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# 数字是有限的
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## 描述
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`Number.isFinite()`方法检查传入其中的值是否为有限数。这种方法是在ES6中引入的
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## 句法
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`Number.isFinite(val)`
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### 参数
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**val** - 检查有限性的值
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## 返回值
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一个[布尔值，](https://guide.freecodecamp.org/javascript/booleans)指示值是否为有限数。
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## 描述
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`Number.isFinite`与全局[isFinite（）](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isFinite)方法不同，它不会将测试值转换为数字。这意味着该值必须是一个数字并且有限以返回true。
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## 例子
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```
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Number.isFinite(Infinity) // false
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Number.isFinite(-Infinity) // false
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Number.isFinite(1234) // true
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Number.isFinite(-1.11) // true
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Number.isFinite(0) // true
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Number.isFinite(3g55) // true
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Number.isFinite('1234') // false
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Number.isFinite('Hi') // false
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Number.isFinite('2005/12/12') // false
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Number.isFinite('0'); // false, would've been true with
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// global isFinite('0')
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Number.isFinite(null); // false, would've been true with
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// global isFinite(null)
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```
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#### 更多信息：
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[ECMA 2015文件](https://www.ecma-international.org/ecma-262/6.0/#sec-number.isfinite) [Number.isFinite（）MDN Web文档](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isFinite)
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