Benchmark: parseFloat isNaN vs RegEx parseFloat vs Number isNaN

Script Preparation code:

var n = "-5";
var regex = /^-?\d+$/;

Tests:

parseFloat isNaN
var v = parseFloat(n); var a = isNaN(v) ? n : v;
RegEx parseFloat
var a = regex.test(n) ? parseFloat(n) : n;
Number isNaN
var v = Number(n); var a = isNaN(v) ? n : v;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
parseFloat isNaN
RegEx parseFloat
Number isNaN

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/109.0.0.0 Safari/537.36

Browser/OS: Chrome 109 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
parseFloat isNaN	3110600.0 Ops/sec
RegEx parseFloat	2911099.8 Ops/sec
Number isNaN	3223382.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark JSON and explain what is tested, compared, and their pros and cons.

**Overview**

The provided benchmark tests three different approaches to convert a string representation of an integer (`-5`) into its numerical value:

1. `parseFloat` with `isNaN`
2. Regular Expression (RegEx) `parseFloat`
3. `Number`

These approaches are compared in terms of performance, which is measured by the number of executions per second.

**Library and Special JS Feature**

The benchmark uses two libraries:

* No explicit library usage for the test cases.
* The `RegExp` object is used in the RegEx `parseFloat` approach.

No special JavaScript features or syntax are used in this benchmark.

**Benchmark Test Cases**

Each test case has a "Benchmark Definition" that specifies how to prepare the input data and perform the conversion:

1. `parseFloat isNaN`: Converts the string `-5` to its numerical value using `parseFloat`, then checks if the result is NaN (Not a Number) and returns either the original string or the numerical value.
2. `RegEx parseFloat`: Uses a regular expression to extract the numeric part from the input string, then converts it to its numerical value using `parseFloat`.
3. `Number`: Converts the input string `-5` directly to its numerical value using the `Number` function.

**Performance Comparison**

The benchmark results show that:

* The `Number` approach has the highest performance (322,338 executions per second).
* The RegEx `parseFloat` approach is slower than both `Number` and `parseFloat isNaN`.
* The `parseFloat isNaN` approach performs similarly to the RegEx `parseFloat` approach.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **Number**: Pros:
	* Fastest execution time.
	* Simple implementation.
Cons:
	+ Does not handle non-numeric input strings correctly.
2. `parseFloat isNaN`: Pros:
	+ Handles non-numeric input strings by returning the original string.
	+ Performs similarly to RegEx `parseFloat`.
Cons:
	+ May incur overhead due to the explicit check for NaN.
3. **RegEx parseFloat**: Pros:
	+ Can handle non-numeric input strings by returning the original string.
Cons:
	+ Slower execution time compared to `Number` and `parseFloat isNaN`.

**Alternatives**

Other alternatives to these approaches include:

1. Using a `Try-Catch` block with `NaN` to catch any errors that occur during the conversion process.
2. Implementing custom parsing logic for specific input formats.
3. Utilizing other libraries or modules, such as `parse-int` or `decimal.js`, which provide optimized implementations for converting strings to numbers.

Keep in mind that these alternatives may not necessarily offer significant performance improvements over the tested approaches but can provide additional functionality or flexibility.

Related benchmarks:

parseFloat isNaN vs RegEx parseFloat vs Number isNaN (version: 0)

Comparing performance of: parseFloat isNaN vs RegEx parseFloat vs Number isNaN

Created: one year ago by: Guest

Jump to the latest result

parseFloat isNaN

RegEx parseFloat

Number isNaN

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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