Benchmark: typeof x === 'number' vs isNaN(x)

Tests:

typeof
typeof 5 === 'number'
isNaN
isNaN(5)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
isNaN

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 23 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser/OS: Chrome 134 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
typeof	62539308.0 Ops/sec
isNaN	39175724.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided JSON and explain what's being tested.

**Benchmark Overview**

The benchmark is comparing two options:

1. `typeof x === 'number'`
2. `isNaN(x)`

These two expressions are used to check if a variable `x` is a number.

**Options Compared**

The benchmark is testing two approaches to achieve the same goal: checking if a value is a number. The first approach uses the `typeof` operator, and the second approach uses the `isNaN()` function (which checks if a value is Not A Number).

**Pros and Cons of Each Approach**

1. **typeof x === 'number'**
	* Pros:
		+ Straightforward and easy to read.
		+ Works in most browsers, including older ones that don't support `NaN()`.
	* Cons:
		+ Can be slower than using `isNaN()` because it performs a type check.
		+ May not work as expected in certain edge cases (e.g., NaN values returned by functions).
2. **isNaN(x)**
	* Pros:
		+ Faster than `typeof` because it only checks if the value is Not A Number.
		+ Works well for checking NaN values and other non-numeric types.
	* Cons:
		+ May return false positives if the input value is a non-numeric type (e.g., string, object).
		+ Requires understanding of how `isNaN()` works to interpret results correctly.

**Library Usage**

There is no explicit library mentioned in the JSON. However, it's worth noting that some browsers may have internal libraries or helper functions that can be used for tasks like this. For example, some browsers may have a built-in function called `Number.isNaN()` that behaves similarly to the `isNaN()` function.

**Special JavaScript Features/Syntax**

There are no special JavaScript features or syntax mentioned in the JSON. The tests only involve standard JavaScript operators and functions (e.g., `typeof`, `isNaN`).

**Other Alternatives**

If you were to rewrite this benchmark using a different approach, some alternatives could be:

* Using a library like Fast.js or Litmus.js that provides benchmarking tools.
* Implementing the test in a language like C++ and compiling it to JavaScript using a tool like Emscripten.
* Using a different testing framework or library, such as Jest or Mocha.

However, for most use cases, the simple `typeof` vs. `isNaN()` approach is sufficient, and the benchmark can focus on comparing the performance of these two options in different browsers.

Related benchmarks:

typeof x === 'number' vs isNaN(x) (version: 0)

Comparing performance of: typeof vs isNaN

Created: 4 years ago by: Guest

Jump to the latest result

typeof

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):