Benchmark: typeof number vs. Number.isNan vs. isNan vs self comparison

Tests:

typeof
typeof 5 === 'number'
Number.isNan
Number.isNaN(5)
isNaN
isNaN(5)
Self comparison
5 !== 5

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
Number.isNan
isNaN
Self comparison

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Mac OS X 10.15.7

View result in a separate tab

typeof

1003.9M/s

Self comparison

1001.3M/s

Number.isNan

17.6M/s

isNaN

17.5M/s

View exact numbers

Test name	Executions per second
✓ typeof	1,003,869,952 Ops/sec
Self comparison	1,001,263,872 Ops/sec
Number.isNan	17,585,696 Ops/sec
isNaN	17,496,074 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided JSON represents a JavaScript microbenchmarking test case created on MeasureThat.net. The benchmark tests four different approaches to check if a value is a number: `typeof`, `Number.isNaN`, `isNaN`, and self-comparison using the `!==` operator.

**Options Compared**

1. **`typeof 5 === 'number'`**: This approach uses the `typeof` operator in combination with a string comparison (`===`) to check if the value is a number. The `typeof` operator returns a string indicating the type of the variable, and by comparing it to `'number'`, we can determine if the value is indeed a number.
2. **`Number.isNaN(5)`**: This approach uses the `Number.isNaN()` function, which checks if a given value is NaN (Not a Number).
3. **`isNaN(5)`**: This approach uses the `isNaN()` function, which returns `true` if the value is NaN and `false` otherwise.
4. **`5 !== 5`**: This approach uses self-comparison with the `!==` operator to check if the value is not equal to itself (i.e., it's a number).

**Pros and Cons of Each Approach**

1. **`typeof 5 === 'number'`**:
	* Pros: Fast and simple.
	* Cons: May be slower for non-numeric values, as `typeof` returns a string literal, which can lead to unnecessary overhead.
2. **`Number.isNaN(5)`**: This approach is not available in older browsers that don't support ECMAScript 2017 (ES7) standard.
3. **`isNaN(5)`**:
	* Pros: Similar speed to `typeof` for numeric values, as it only checks if the value is NaN.
	* Cons: May be slower for non-numeric values, as it's a separate function call.
4. **`5 !== 5`**: This approach is simple and fast, but it assumes that the value being compared is a number.

**Library Used**

None of these approaches rely on external libraries.

**Special JS Feature or Syntax**

There are no special features or syntax used in this benchmark.

**Considerations**

* For numeric values, all four approaches have similar performance.
* For non-numeric values (e.g., strings), the `typeof` approach may be slower due to unnecessary string comparisons.
* Older browsers may not support the `Number.isNaN()` and `isNaN()` functions.

**Other Alternatives**

If you need a more robust or modern way of checking if a value is a number, consider using:

1. **`Number` constructor**: Creates a new number object from a given value.
2. **`instanceof Number` operator**: Checks if an object is an instance of the `Number` class.

However, these alternatives may not be supported in older browsers and may have different performance characteristics compared to the original approaches tested here.

typeof number vs. Number.isNan vs. isNan vs self comparison (version: 0)

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

Created: 2 years ago by: Guest

Go to the latest result

typeof

Number.isNan

isNaN

Self comparison

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

typeof number vs. Number.isNan vs. isNan vs self comparison (version: 0)

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

Created: 2 years ago by: Guest

Go to the latest result

typeof

Number.isNan

isNaN

Self comparison

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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