JavaScript Number isFinite() method

The JavaScript number isFinite() method determines whether the given value is a finite number. It returns true if the value is a finite number, otherwise it returns false.

Syntax

The isFinite() method is represented by the following syntax:

Parameter

num - A number to be checked.

Return

A Boolean value.

JavaScript Number isFinite() method example

Here, we will understand isFinite() method through various examples.

Example 1

Let's see a simple example of isFinite() method.

<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>

Test it Now

Output:

true true true

Example 2

In this example, we will use isFinite() method with negative numbers.

<script>
function check(x,y)
{
  return x/y;
}
document.writeln(Number.isFinite(check(0,10)));
document.writeln(Number.isFinite(check(10,0))); 
</script>

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Output:

true false

Example 3

Let's see isFinite() method with some different test cases.

<script>
document.writeln(Number.isFinite(Infinity));
document.writeln(Number.isFinite(-Infinity));
document.writeln(Number.isFinite(NaN)); 
</script>

Test it Now

Output: