Benchmark: 1d170c5a-bf42-4104-b3a4-9ccbdcb4f20b

Script Preparation code:

var a = 5

Tests:

typeof
typeof a === 'number'
Number.isNan
Number.isNaN(a)
isNaN
isNaN(a)
Self comparison
a !== a
Number.isFinite
Number.isFinite(a)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
Number.isNan
isNaN
Self comparison
Number.isFinite

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark JSON and individual test cases to understand what is being tested.

**Benchmark Definition JSON**

The benchmark definition represents a JavaScript function or expression that is being measured for performance. In this case, it contains two parts:

1. **Script Preparation Code**: This is a piece of JavaScript code that is executed before running the benchmarked expression. In this case, it sets the variable `a` to 5.
2. **Html Preparation Code**: This section is empty, which means no HTML code is being prepared for the benchmark.

**Individual Test Cases**

Each test case represents a specific JavaScript function or expression being tested for performance. There are five individual test cases:

1. `typeof a === 'number'`: Tests whether the type of variable `a` is "number".
2. `Number.isNaN(a)`: Tests whether `a` is NaN (Not a Number).
3. `isNaN(a)`: Tests whether `a` is NaN using the `isNaN()` function.
4. `a !== a`: Performs self-comparison, checking if `a` is not equal to itself.
5. `Number.isFinite(a)`: Tests whether `a` is finite (not infinite).

**Libraries and Special JS Features**

None of the test cases explicitly use any libraries or special JavaScript features beyond the standard library functions provided by JavaScript.

**Options Comparison**

The options being compared are:

1. **Using `typeof`**: Verifies if the type of a variable is "number".
2. **Using `Number.isNaN()`**: Checks if a value is NaN.
3. **Using `isNaN()`**: Checks if a value is NaN (this function returns true for both NaN and undefined values).
4. **Self-comparison (`a !== a`)**: Compares the value of `a` with itself, which will always be false.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

1. `typeof`:
	* Pros: Simple, straightforward, and widely supported.
	* Cons: May not work as expected for certain data types (e.g., NaN or null).
2. `Number.isNaN()`:
	* Pros: More accurate than `isNaN()`, handles NaN values correctly.
	* Cons: Less intuitive than using `typeof`.
3. `isNaN()`:
	* Pros: Simple and widely supported, returns true for both NaN and undefined values.
	* Cons: Not as accurate as `Number.isNaN()` and may return incorrect results for NaN values.

**Other Considerations**

When choosing between these options, consider the specific requirements of your project:

* If you need to check if a value is not a number, use `typeof` or `isNaN()`.
* If you need to accurately identify NaN values, use `Number.isNaN()`.
* For self-comparison, it's unlikely that this approach will provide meaningful results.

**Alternatives**

If these options are not sufficient for your needs, consider the following alternatives:

1. **Use a more advanced comparison library**: Depending on your specific requirements, you might need to look into libraries like Lodash or Ramda.
2. **Implement custom implementation**: If none of the above options meet your needs, consider implementing your own custom function for comparing values.

In summary, this benchmark compares the performance of five different approaches to checking if a variable is not equal to itself or is NaN. The choice of approach depends on specific requirements and trade-offs between simplicity, accuracy, and performance.

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36

Browser/OS: Chrome 127 on Linux

View result in a separate tab

Test name	Executions per second
typeof	29669578.0 Ops/sec
Number.isNan	11624371.0 Ops/sec
isNaN	11461264.0 Ops/sec
Self comparison	15505890.0 Ops/sec
Number.isFinite	11217465.0 Ops/sec

Related benchmarks:

1d170c5a-bf42-4104-b3a4-9ccbdcb4f20b (version: 0)

Comparing performance of: typeof vs Number.isNan vs isNaN vs Self comparison vs Number.isFinite

Created: 3 months ago by: Guest

Jump to the latest result

typeof

Number.isNan

isNaN

Self comparison

Number.isFinite

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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