The isFinite function in JavaScript assesses if a specified value is a finite number. It yields true when the value represents a finite number; otherwise, it produces false.
Syntax
The syntax for the isFinite method is expressed as follows:
Example
Number.isFinite(num)
Parameter
num - A number to be checked.
Return
A Boolean value.
JavaScript Number isFinite method example
In this section, we will explore the isFinite method by examining several examples.
Example 1
Let's see a simple example of isFinite method.
Example
<script>
var x=0;
var y=1;
var z=-1;
document.writeln(Number.isFinite(x));
document.writeln(Number.isFinite(y));
document.writeln(Number.isFinite(z));
</script>
Output:
Output
true true true
Example 2
In this illustration, we will demonstrate the use of the isFinite method with negative numerical values.
Example
<script>
function check(x,y)
{
return x/y;
}
document.writeln(Number.isFinite(check(0,10)));
document.writeln(Number.isFinite(check(10,0)));
</script>
Output:
Output
true false
Example 3
Let’s examine the isFinite function through various test scenarios.
Example
<script>
document.writeln(Number.isFinite(Infinity));
document.writeln(Number.isFinite(-Infinity));
document.writeln(Number.isFinite(NaN));
</script>
Output:
Output
false false false
