Benchmark: isNaN(input) vs Number.isNaN(Number(input))

Script Preparation code:

function testImplicitConversionStringToNaN(input) {
    return isNaN(input);
}

function testStrictnessConversionStringToNaN(input) {
    return Number.isNaN(Number(input));
}

Tests:

Implicit conversion test
testImplicitConversionStringToNaN('123'); testImplicitConversionStringToNaN('123abc'); testImplicitConversionStringToNaN(NaN); testImplicitConversionStringToNaN(null); testImplicitConversionStringToNaN({}); testImplicitConversionStringToNaN(123);
Strictness conversion test
testStrictnessConversionStringToNaN('123'); testStrictnessConversionStringToNaN('123abc'); testStrictnessConversionStringToNaN(NaN); testStrictnessConversionStringToNaN(null); testStrictnessConversionStringToNaN({}); testStrictnessConversionStringToNaN(123);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Implicit conversion test
Strictness conversion test

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 months 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
Implicit conversion test	1546049.0 Ops/sec
Strictness conversion test	1094430.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided JSON represents a JavaScript benchmark that compares two approaches for testing if a value is NaN (Not a Number). The benchmark consists of two main parts:

1. **Implicit Conversion**: This approach uses the `isNaN()` function to test if a value is NaN. The implicit conversion occurs when a string is implicitly converted to a number using the `Number()` function or by simply assigning a numeric value to a variable.
2. **Strictness Conversion**: This approach uses the `Number.isNaN()` function to test if a value is NaN. The strictness conversion involves explicitly converting the input value to a number using the `Number()` function and then comparing it with `NaN`.

**Comparing Options**

The two approaches have different performance characteristics:

* **Implicit Conversion (isNaN())**: This approach can be faster for some inputs, as it avoids the overhead of explicit type conversions. However, it may also lead to incorrect results if the input value is not a number.
* **Strictness Conversion (Number.isNaN())**: This approach ensures that only numbers are converted to `NaN`, reducing the likelihood of incorrect results.

**Pros and Cons**

**Implicit Conversion:**
Pros:

* Faster for some inputs
Cons:

* May lead to incorrect results if input values are not numbers

**Strictness Conversion:**
Pros:

* Ensures accurate results by avoiding implicit type conversions
Cons:

* May be slower due to the explicit conversion step

**Other Considerations**

When choosing between these approaches, consider the following factors:

* **Input Values**: If you're working with non-numeric input values, strictness conversion is generally safer. However, if your inputs are mostly numeric, implicit conversion might be faster.
* **Performance**: If speed is crucial, implicit conversion might be a better choice. However, ensure that your specific use case doesn't rely on incorrect results.

**Library: None**

There is no external library used in this benchmark.

**Special JS Feature or Syntax: None**

This benchmark does not utilize any special JavaScript features or syntax beyond standard JavaScript functions like `isNaN()` and `Number.isNaN()`.

Related benchmarks:

isNaN(input) vs Number.isNaN(Number(input)) (version: 0)

benchmark for using: - implicit conversion of string to number -> isNaN(input) vs - strictness conversion of string to number and after it compare with NaN -> Number.isNaN(Number(input))

Comparing performance of: Implicit conversion test vs Strictness conversion test

Created: one year ago by: Guest

Jump to the latest result

Implicit conversion test

Strictness conversion test

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):