Benchmark: isFinite vs is undefined

Script Preparation code:

varsToCheck = [3, 3.14, "some string", null, undefined];
count = 0;

Tests:

isFinite
varsToCheck.forEach(function(v){ if(Number.isFinite(v)) { count++ } });
is undefined
varsToCheck.forEach(function(v){ if(v !== undefined) { count++ } });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
isFinite
is undefined

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:123.0) Gecko/20100101 Firefox/123.0

Browser/OS: Firefox 123 on Windows

View result in a separate tab

Test name	Executions per second
isFinite	8673759.0 Ops/sec
is undefined	9934898.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Benchmark Overview**

The benchmark is designed to measure the performance difference between two JavaScript methods: `isFinite()` and checking for `undefined`. The goal is to compare how these methods perform when iterating over an array of values.

**Variables being tested**

The variables being tested are:

* `varsToCheck`: an array containing various values, including numbers (`3` and `3.14`), strings (`"some string"`), and special values (`null` and `undefined`).

**Benchmark methods compared**

There are two benchmark methods being compared:

1. **isFinite()**: This method checks if a value is finite (i.e., not NaN or infinity).
2. **Checking for undefined**: This method simply checks if the value is equal to `undefined`.

**Pros and Cons of each approach:**

* **isFinite():**
	+ Pros:
		- More comprehensive check, as it also handles NaN values.
		- Can be more efficient than checking for `undefined`, as it can short-circuit early.
	+ Cons:
		- May have performance overhead due to the additional check.
		- Not necessary if the only concern is detecting `undefined` values.
* **Checking for undefined:**
	+ Pros:
		- Simple and lightweight, with minimal overhead.
		- Only checks for `undefined`, which might be sufficient in some cases.
	+ Cons:
		- Does not handle NaN or infinity values, which can lead to incorrect results.

**Libraries and special features**

In this benchmark, the following library is used:

* **Number.isFinite()**: This method was introduced in ECMAScript 2015 (ES6). It's a more modern alternative to `isFinite()` that also handles NaN values. If your JavaScript environment doesn't support ES6, you may need to use an older version of this function.

**Other considerations**

When writing benchmarks like this one, consider the following:

* Use a representative set of test data to ensure fairness.
* Choose benchmarking tools and libraries that are well-suited for your specific use case (e.g., MeasureThat.net).
* Keep in mind that browser performance can vary significantly depending on factors like hardware, operating system, and version.

**Alternative benchmarks**

If you'd like to explore other types of benchmarks, consider the following:

* **Array size variations**: Compare the performance of `isFinite()` and checking for `undefined` when iterating over arrays with different sizes.
* **Null or NaN values**: Add null or NaN values to your test data to see how these affect performance.
* **Browser-specific optimizations**: Test how different browsers handle these benchmarks, as some might have built-in optimizations or differences in implementation.

I hope this explanation helps you understand the benchmark and its design!

Related benchmarks:

isFinite vs is undefined (version: 0)

Comparing performance of: isFinite vs is undefined

Created: 2 years ago by: Guest

Jump to the latest result

isFinite

is undefined

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):