Benchmark: typeof vs typeof isNaN

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
isNaN(5)
typeof

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 YaBrowser/24.7.0.0 Safari/537.36

Browser/OS: Yandex Browser 24 on Windows

View result in a separate tab

Test name	Executions per second
isNaN(5)	7219921.5 Ops/sec
typeof	6785834.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**What is being tested?**

The provided benchmark tests the performance difference between using `typeof` and `isNaN` to check if a value is a number.

**Options compared:**

There are two options being compared:

1. `typeof 5 === 'number'`: This checks if the result of calling `typeof` on the value 5 is equal to the string `'number'`.
2. `isNaN(5)`: This checks if the value 5 is not an infinite number (i.e., NaN - Not a Number).

**Pros and Cons:**

1. **`typeof`**: The `typeof` operator returns a string indicating the type of the value. If the value is 'number', it will return `'number'`. However, this approach has some pitfalls:
	* It can be slower than `isNaN` because it involves a string comparison.
	* It may not work as expected for certain types of values (e.g., NaN).
2. **`isNaN`**: The `isNaN` function checks if the value is not an infinite number. This approach is generally faster and more reliable:
	* However, it can be slower than checking for a specific string using `typeof`.
	* It may not work as expected for certain types of values (e.g., NaN).

**Library:**

There is no explicit library mentioned in the benchmark definition or test cases. The `isNaN` function is a built-in JavaScript function.

**Special JS feature/syntax:**

None are explicitly used in this benchmark.

**Other alternatives:**

In general, when checking if a value is a number, you can also use other approaches:

1. `Number.isFinite(value)`: This checks if the value is finite (i.e., not NaN or infinity).
2. `Number.isInteger(value)`: This checks if the value is an integer.
3. Using a library like Lodash's `isNumber` function.

Keep in mind that these alternatives may have slightly different performance characteristics and use cases compared to `typeof` and `isNaN`.

**Benchmark preparation code:**

The provided JSON doesn't include any specific benchmark preparation code. This means that the script will simply run the provided benchmark definitions without any setup or cleanup.

Overall, this benchmark is a simple test of performance between two common ways to check if a value is a number in JavaScript.

Related benchmarks:

typeof vs typeof isNaN (version: 2)

Comparing performance of: isNaN(5) vs typeof

Created: 2 years ago by: Registered User

Jump to the latest result

isNaN(5)

typeof

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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