50 lines
1.5 KiB
Markdown
50 lines
1.5 KiB
Markdown
|
---
|
|||
|
title: Number isFinite
|
|||
|
localeTitle: 数字是有限的
|
|||
|
---
|
|||
|
# 数字是有限的
|
|||
|
|
|||
|
## 描述
|
|||
|
|
|||
|
`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
|
|||
|
|
|||
|
## 句法
|
|||
|
|
|||
|
`Number.isFinite(val)`
|
|||
|
|
|||
|
### 参数
|
|||
|
|
|||
|
**val** - 检查有限性的值
|
|||
|
|
|||
|
## 返回值
|
|||
|
|
|||
|
一个[布尔值,](https://guide.freecodecamp.org/javascript/booleans)指示值是否为有限数。
|
|||
|
|
|||
|
## 描述
|
|||
|
|
|||
|
`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。
|
|||
|
|
|||
|
## 例子
|
|||
|
```
|
|||
|
Number.isFinite(Infinity) // false
|
|||
|
Number.isFinite(-Infinity) // false
|
|||
|
|
|||
|
Number.isFinite(1234) // true
|
|||
|
Number.isFinite(-1.11) // true
|
|||
|
Number.isFinite(0) // true
|
|||
|
Number.isFinite(3g55) // true
|
|||
|
|
|||
|
Number.isFinite('1234') // false
|
|||
|
Number.isFinite('Hi') // false
|
|||
|
Number.isFinite('2005/12/12') // false
|
|||
|
|
|||
|
Number.isFinite('0'); // false, would've been true with
|
|||
|
// global isFinite('0')
|
|||
|
|
|||
|
Number.isFinite(null); // false, would've been true with
|
|||
|
// global isFinite(null)
|
|||
|
```
|
|||
|
|
|||
|
#### 更多信息:
|
|||
|
|
|||
|
[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)
|