Unlock the Power of Finite Numbers
When working with numbers in JavaScript, it’s essential to know whether a value is finite or not. This is where the isFinite() function comes into play. But what exactly does it do, and how can you harness its power?
The Syntax
The isFinite() function takes a single parameter, testValue, which is the value to be tested for finiteness. The syntax is straightforward: isFinite(testValue).
Return Values
So, what does isFinite() return? The answer is simple:
falseif the argument is Infinity, NaN (Not a Number), or undefinedtruefor all other arguments
Real-World Examples
Let’s put isFinite() to the test! In our first example, we’ll check if the value 5463 is finite. As expected, the output is true, since 5463 is a finite number.
But what about Infinity and undefined? In our second example, we’ll see that isFinite() returns false for these values, as expected.
And what about NaN (Not a Number) and null? In our third example, we’ll see that isFinite() returns false for these values as well.
A Key Benefit
One of the most significant advantages of isFinite() is that it’s a top-level function, meaning it’s not associated with any object or class. This means you can call it from anywhere without creating an instance, making it a convenient and powerful tool in your JavaScript toolkit.
Related Topic: isNaN()
If you’re interested in learning more about working with numbers in JavaScript, be sure to check out the isNaN() function, which checks if a value is Not a Number (NaN).