Benchmark: isFinite vs isNaN

Tests:

isFinite
Number.isFinite(123)
isNaN
Number.isNaN(123)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
isFinite
isNaN

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser/OS: Firefox 115 on Windows 8.1

View result in a separate tab

Test name	Executions per second
isFinite	107620544.0 Ops/sec
isNaN	101112056.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its test cases to understand what's being tested.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark called "isFinite vs isNaN". This benchmark compares the performance of two different methods for checking if a number is finite or not: `Number.isFinite()` and `Number.prototype.isNaN()`. In other words, it tests which method is faster for determining whether a given number is either finite (i.e., not NaN) or infinite.

**Options compared**

There are two options being compared:

1. **`Number.isFinite(123)`**: This option checks if the number 123 is finite by using the `isFinite()` method.
2. **`Number.prototype.isNaN(123)`**: This option checks if the number 123 is NaN (Not a Number) by using the `isNaN()` method, which is a property of the Number prototype.

**Pros and cons**

Here are some pros and cons of each approach:

1. **`Number.isFinite(123)`**:
	* Pros: It's a more explicit way to check for finiteness.
	* Cons: It may be slower than using `isNaN()` because it requires a function call and additional checks.
2. **`Number.prototype.isNaN(123)`**:
	* Pros: It's faster and more efficient, as it only requires accessing the `NaN` property on the Number prototype.
	* Cons: The method name might be less intuitive for some developers.

In general, using `isNaN()` is a good practice when working with numbers in JavaScript, but using `isFinite()` can provide additional clarity and explicitness in certain situations.

**Library**

There is no specific library used in this benchmark. However, the `Number` object and its prototype (`Number.prototype`) are part of the JavaScript standard library.

**Special JS feature or syntax**

This benchmark does not use any special JavaScript features or syntax beyond what's already mentioned. Both `isFinite()` and `isNaN()` are built-in methods that have been available in JavaScript since its inception.

**Other alternatives**

Some alternative ways to check for finiteness include:

1. **`Number.EPSILON`**: This is a small value that can be used to determine whether two numbers are close enough to be considered equal (i.e., not NaN). However, this approach requires careful handling and is generally less reliable than using `isFinite()` or `isNaN()`.
2. **`Math.abs(x) === x`**: This method checks if the absolute value of a number equals the original value, which can be used to detect NaN values.

Keep in mind that these alternatives may not provide the same level of clarity and readability as using the built-in `isFinite()` or `isNaN()` methods.

Related benchmarks:

isFinite vs isNaN (version: 0)

Comparing performance of: isFinite vs isNaN

Created: one year ago by: Registered User

Jump to the latest result

isFinite

isNaN

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):