Benchmark: toFixed vs toPrecision vs Math.round() - Return number

Script Preparation code:

var someFloat = 0.123456789;

Tests:

toFixed(4)
parseFloat(someFloat.toFixed(4));
toPrecision(4).toString()
parseFloat(someFloat.toPrecision(4));
(Math.round(*10000)/10000).toString()
(Math.round(someFloat*10000)/10000);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
toFixed(4)
toPrecision(4).toString()
(Math.round(*10000)/10000).toString()

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 15_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.2 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 15 on iOS 15.2

View result in a separate tab

Test name	Executions per second
toFixed(4)	4459111.0 Ops/sec
toPrecision(4).toString()	4180885.0 Ops/sec
(Math.round(*10000)/10000).toString()	7729869.0 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 provided benchmark and explain what is being tested.

**Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark compares the performance of three different methods for rounding a floating-point number:

1. `toFixed`
2. `toPrecision`
3. `Math.round`

The benchmark uses a sample float value (`someFloat = 0.123456789`) and applies each method to it, converting the result to a string using `.toString()`.

**What is being tested?**

In essence, this benchmark tests the performance of three different rounding methods:

1. **`toFixed`**: This method takes an optional number of decimal places as an argument and returns a string representing the float value with that many decimal places.
2. **`toPrecision`**: This method takes an integer value (the precision) as an argument and returns a string representing the float value with that many significant digits.
3. **`Math.round`**: This built-in JavaScript function rounds a number to the nearest integer.

The benchmark compares the performance of these three methods across different devices (iPhone, Mobile Safari 15 on iOS 15.2) by executing each test case multiple times and measuring the total executions per second.

**Pros and cons of each approach**

1. **`toFixed`**:
	* Pros: Simple and intuitive API, easy to use.
	* Cons: May introduce unnecessary decimal places if not specified, can be slower than other methods due to string conversion.
2. **`toPrecision`**:
	* Pros: More flexible than `toFixed`, allows for rounding to any number of significant digits.
	* Cons: May require more complex code to use correctly, can be slower due to string conversion.
3. **`Math.round`**:
	* Pros: Fast and efficient, widely supported by browsers.
	* Cons: Rounds to the nearest integer, may not produce the desired result if the input is very close to an integer.

**Other considerations**

* The benchmark uses `.toString()` to convert each method's result to a string. This introduces additional overhead, as strings are generally slower than numbers in JavaScript.
* The sample float value used in the benchmark (`someFloat = 0.123456789`) is not particularly large or complex, which may affect the results.

**Alternatives**

If you need more control over rounding or want to explore alternative methods, consider using:

* `Number.EPSILON`: A small value that represents the difference between 1 and a normalized float value. You can use this to determine the smallest unit of measurement for your application.
* `Big.js` or `Decimal.js`: JavaScript libraries specifically designed for decimal arithmetic and rounding.

Keep in mind that these alternatives may introduce additional complexity and dependencies, so be sure to weigh the trade-offs before choosing an alternative approach.

Related benchmarks:

toFixed vs toPrecision vs Math.round() - Return number (version: 0)

Comparing performance of: toFixed(4) vs toPrecision(4).toString() vs (Math.round(*10000)/10000).toString()

Created: 2 years ago by: Guest

Jump to the latest result

toFixed(4)

toPrecision(4).toString()

(Math.round(*10000)/10000).toString()

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):