isFinite()
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
该全局 isFinite()
函数用来判断被传入的参数值是否为一个有限数值(finite number)。在必要情况下,参数会首先转为一个数值。
尝试一下
function div(x) {
if (isFinite(1000 / x)) {
return "Number is NOT Infinity.";
}
return "Number is Infinity!";
}
console.log(div(0));
// Expected output: "Number is Infinity!""
console.log(div(1));
// Expected output: "Number is NOT Infinity."
语法
js
isFinite(testValue)
参数
testValue
-
用于检测有限性(finiteness)的值。
描述
isFinite 是全局的方法,不与任何对象有关系。
你可以用这个方法来判定一个数字是否是有限数字。isFinite
方法检测它参数的数值。如果参数是 NaN
,正无穷大或者负无穷大,会返回false
,其他返回 true
。
示例
js
isFinite(Infinity); // false
isFinite(NaN); // false
isFinite(-Infinity); // false
isFinite(0); // true
isFinite(2e64); // true,在更强壮的 Number.isFinite(null) 中将会得到 false
isFinite("0"); // true,在更强壮的 Number.isFinite('0') 中将会得到 false
规范
Specification |
---|
ECMAScript® 2025 Language Specification # sec-isfinite-number |
浏览器兼容性
Report problems with this compatibility data on GitHubdesktop | mobile | server | ||||||||||||
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isFinite |
Legend
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- Full support
- Full support
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