JavaScript isFinite()
Examples
Check if a number is finite:
let result = isFinite(123);
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let result = isFinite("123");
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Description
The isFinite() method returns true
if a value is a finite number.
Infinite (not finite) values are Infinity,
-Infinity, or NaN
See Also:
Difference Between isFinite() and Number.isFinite()
isFinite() returns true if a value is a finite number.
Number.isFinite() returns true if a number is a finite number.
In other words:
isFinite() converts the value to a number before testing it.
Examples
// This returns true
isFinite(123)
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isFinite(123)
// This returns false
Number.isFinite("123")
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Number.isFinite("123")
Syntax
isFinite(value)
Parameters
Parameter
Description
value
Required.
The value to be tested.
The value to be tested.
Return Value
Type
Description
A boolean.
Otherwise
false if the value is Infinity,
-Infinity, or NaN.Otherwise
true.
More Examples
Check if a number is finite:
isFinite(-1.23);
isFinite(5-2);
isFinite(0);
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isFinite(5-2);
isFinite(0);
isFinite("Hello");
isFinite("2005/12/12");
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isFinite("2005/12/12");
Browser Support
isFinite() is an ECMAScript1 (JavaScript 1997) feature.
It is supported in all browsers:
| Chrome | Edge | Firefox | Safari | Opera | IE |
| Yes | Yes | Yes | Yes | Yes | Yes |