Benchmark: toFixed vs Math.round() with numbers

Script Preparation code:

var someFloat = 18.99;

Tests:

Number(toFixed())
Number((someFloat * 100).toFixed());
Math.round(someFloat*100);
(Math.round(someFloat*10000)/10000).toString();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Number(toFixed())
Math.round(someFloat*100);

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
Number(toFixed())	5131887.5 Ops/sec
Math.round(someFloat*100);	8389816.0 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 benchmark and explain what is being tested, compared, and their pros and cons.

**What is being tested?**

The benchmark is testing two different approaches to rounding numbers: `toFixed()` and `Math.round()`. The tests are comparing the performance of these two methods when applied to a specific number `someFloat` (which is set in the script preparation code).

**Options compared:**

1. **Number(toFixed())**: This approach uses the `toFixed()` method to convert the floating-point number to a string, and then uses the built-in `Number()` function to parse it back into a number. The precision of the conversion is not specified.
2. **Math.round(someFloat*100);**: This approach uses the `Math.round()` function to round the number to two decimal places (due to the multiplication by 100). It does not involve any explicit string conversion.

**Pros and Cons:**

1. **Number(toFixed())**:
	* Pros:
		+ Can be used with arbitrary precision, as it doesn't involve a fixed rounding step.
		+ May be more accurate for certain use cases where precision is important.
	* Cons:
		+ Involves an extra step of string conversion and parsing, which can lead to performance overhead.
		+ Precision may not be immediately apparent without explicit configuration (e.g., `toFixed(2)`).
2. **Math.round(someFloat*100);**:
	* Pros:
		+ Involves no explicit string conversion, making it potentially faster.
		+ Provides a fixed rounding precision of two decimal places, which can simplify subsequent calculations.
	* Cons:
		+ Rounding is limited to two decimal places, which may not be suitable for all use cases.
		+ Requires an additional multiplication step, which can introduce overhead.

**Library and special JS feature:**

There is no explicit library or special JavaScript feature being used in these benchmark tests. However, the use of `toFixed()` does involve a built-in method that is part of the JavaScript standard library. This method is implemented in the browser's JavaScript engine (in this case, Chrome) and is not specific to any particular library.

**Other alternatives:**

If you were to rewrite these tests using alternative methods, some possibilities could include:

* Using a different rounding algorithm, such as banker's rounding or round-half-to-even.
* Implementing a custom rounding function that takes into account the context and requirements of your application.
* Comparing performance with other JavaScript libraries or frameworks that provide rounding functions (e.g., MathJS).
* Experimenting with alternative string formatting methods, such as using template literals or regex.

Keep in mind that these alternatives may change the behavior or performance characteristics of the benchmark tests.

Related benchmarks:

toFixed vs Math.round() with numbers (version: 0)

Comparing performance of: Number(toFixed()) vs Math.round(someFloat*100);

Created: one year ago by: Guest

Jump to the latest result

Number(toFixed())

Math.round(someFloat*100);

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):