Benchmark: toFixed vs toPrecision vs Math.round() vs toLocaleString

Script Preparation code:

var someFloat = 0.123456789;

Tests:

toFixed(4)
someFloat.toFixed(4);
toPrecision(4).toString()
someFloat.toPrecision(4).toString();
(Math.round(*10000)/10000).toString()
(Math.round(someFloat*10000)/10000).toString();
toLocaleString("en-gb", {minimumFractionDigits: 0, maximumFractionDigits: 4})
someFloat.toLocaleString("en-gb", {minimumFractionDigits: 0, maximumFractionDigits: 4})

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()
toLocaleString("en-gb", {minimumFractionDigits: 0, maximumFractionDigits: 4})

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36

Browser/OS: Chrome 105 on Windows

View result in a separate tab

Test name	Executions per second
toFixed(4)	6681971.0 Ops/sec
toPrecision(4).toString()	7118705.5 Ops/sec
(Math.round(*10000)/10000).toString()	6548461.0 Ops/sec
toLocaleString("en-gb", {minimumFractionDigits: 0, maximumFractionDigits: 4})	59803.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of what's being tested in the provided JSON benchmark.

**Tested Options**

The test compares four different methods to format or round a floating-point number:

1. `toFixed(4)`: Rounds the float to 4 decimal places, padding with zeros if necessary.
2. `toPrecision(4).toString()`: Rounds the float to 4 significant digits (not necessarily decimal places) and converts it to a string.
3. `(Math.round(*10000)/10000).toString()`: Rounds the float by multiplying by 10,000, rounding to the nearest integer using Math.round(), and then dividing by 10,000 before converting to a string.
4. `toLocaleString("en-gb", {minimumFractionDigits: 0, maximumFractionDigits: 4})`: Formats the float as a localized string with 4 fractional digits.

**Pros and Cons**

Here's a brief analysis of each approach:

* `toFixed(4)`: Simple and efficient, but may not be suitable for all cases (e.g., rounding to significant figures).
* `toPrecision(4).toString()`: More flexible than `toFixed(4)`, as it rounds to significant digits rather than decimal places. However, this method is less intuitive and might lead to errors if not used correctly.
* `(Math.round(*10000)/10000).toString()`: A more explicit approach, but may be slower due to the multiplication factor.
* `toLocaleString("en-gb", {minimumFractionDigits: 0, maximumFractionDigits: 4})`: Formats the number in a locale-specific way, which might not be desirable if you want a standardized result.

**Library Used**

None of these methods require a specific library. They are all built-in JavaScript functions or simple arithmetic operations.

**Special JS Feature/ Syntax**

There is no special feature or syntax used in this benchmark. The tests only utilize standard JavaScript features.

**Alternatives**

If you need to format numbers differently, consider using libraries like:

* `moment.js` for date and time formatting
* `numeral.js` for number formatting with locale support
* `js-number-format` for more complex number formatting scenarios

For rounding numbers, you can use the `round()` function from the `Math` object or a library like `mathjs`.

Keep in mind that each method has its strengths and weaknesses, and the choice of which one to use depends on your specific requirements and preferences.

Related benchmarks:

toFixed vs toPrecision vs Math.round() vs toLocaleString (version: 0)

Comparing performance of: toFixed(4) vs toPrecision(4).toString() vs (Math.round(*10000)/10000).toString() vs toLocaleString("en-gb", {minimumFractionDigits: 0, maximumFractionDigits: 4})

Created: 2 years ago by: Guest

Jump to the latest result

toFixed(4)

toPrecision(4).toString()

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

toLocaleString("en-gb", {minimumFractionDigits: 0, maximumFractionDigits: 4})

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):