Benchmark: Tyepof vs isFinite

Script Preparation code:

var a = {};

Tests:

typeof
for(let i =0; i < 1000000; i++) { const b = typeof a === 'number'; }
isFinite
for(let i =0; i < 1000000; i++) { const b = Number.isFinite(a); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
isFinite

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Windows

View result in a separate tab

Test name	Executions per second
typeof	3.1 Ops/sec
isFinite	1.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the JavaScript microbenchmark on MeasureThat.net.

**Benchmark Overview**

The benchmark tests two different ways to check if a value is either a number (i.e., has no NaN or Infinity values) using the `typeof` and `isFinite` operators in JavaScript.

**What are we comparing?**

The test cases compare:

1. Using the `typeof` operator to check if a variable `a` is a number.
2. Using the `Number.isFinite()` function (introduced in ECMAScript 2015) to check if a variable `a` is a finite number.

**Pros and Cons of each approach:**

1. **Using typeof**:
	* Pros:
		+ Widely supported across browsers, including older ones.
		+ Simple and easy to understand.
	* Cons:
		+ Can return unexpected results for certain values (e.g., NaN or Infinity).
		+ Not as precise as `Number.isFinite()`.
2. **Using Number.isFinite():**
	* Pros:
		+ More precise than `typeof` in most cases.
		+ Returns false for NaN and Infinity, which can be useful in certain scenarios.
	* Cons:
		+ Introduced in ECMAScript 2015, so may not work in older browsers or versions.

**Library Used:**

None of the test cases explicitly use a library. The `typeof` operator is a built-in JavaScript function, and `Number.isFinite()` is also a built-in function introduced in ECMAScript 2015.

**Special JavaScript Features/Syntax:**

There are no special JavaScript features or syntax used in this benchmark. Both test cases only use standard JavaScript operators and functions.

**Alternative Approaches:**

If you want to implement your own number checking function, you could consider using a combination of the following:

1. Checking for NaN using `isNaN()` or `Number.isNaN()`.
2. Checking for Infinity using `isFinite()` (same as above) or by comparing with specific values like `Infinity` and `-Infinity`.
3. Verifying that the value is an integer by checking if it's an exact integer using `Math.abs()` and `%`.

Keep in mind that each approach has its trade-offs, and the choice ultimately depends on your specific use case and requirements.

The benchmark results provided show that Chrome 126 (a relatively recent browser) performs better for both test cases. However, it's essential to note that browser performance can vary depending on various factors like hardware, operating system, and usage patterns.

Related benchmarks:

Tyepof vs isFinite (version: 0)

Comparing performance of: typeof vs isFinite

Created: 2 years ago by: Guest

Jump to the latest result

typeof

isFinite

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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