Benchmark: toFixed vs toPrecision vs Math.round() to 1 decimal place

Script Preparation code:

var someFloat = 0.123456789;

Tests:

toFixed
someFloat.toFixed(1);
toPrecision
someFloat.toPrecision(1).toString();
rounding
(Math.round(someFloat*10)/10).toString();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
toFixed
toPrecision
rounding

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36

Browser/OS: Chrome 132 on Windows

View result in a separate tab

Test name	Executions per second
toFixed	6270092.0 Ops/sec
toPrecision	8491576.0 Ops/sec
rounding	40590504.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided JSON.

The benchmark is comparing three different methods to round a floating-point number to one decimal place:

1. `toFixed(1)`: This method formats the float as a string, padding it with zeros if necessary, and then returns that string representation of the float. The `1` parameter specifies the minimum number of digits to display.

2. `toPrecision(1).toString()`: This method uses the `toPrecision()` function to convert the float to a string representation, with one precision digit specified. This is similar to using `toFixed()`, but it allows for more control over the resulting string format.

3. `(Math.round(someFloat*10)/10).toString()`: This method multiplies the original float by 10, rounds that result to the nearest integer using `Math.round()`, and then divides it by 10 to "undo" the multiplication. The resulting value is then converted to a string using `toString()`.

**Options Compared:**

* `toFixed(1)` vs `toPrecision(1).toString()`: Both methods achieve similar results, but with some differences in how they handle edge cases and rounding behavior.
	+ Pros:
		- `toFixed(1)` is more straightforward and widely supported across browsers.
		- It's likely to produce identical results as `toPrecision(1).toString()` for most use cases.
	+ Cons:
		- Some older browsers or specific libraries may not support `toPrecision()`.
		- The resulting string format might be slightly different from what `toFixed(1)` would produce.
* `(Math.round(someFloat*10)/10).toString()` vs the other two methods: This method is a more manual, explicit approach to rounding. It's likely to produce identical results as either of the first two methods for most use cases.

**Library/Functions Used:**

* `toFixed()`: A built-in JavaScript function for formatting numbers as strings.
* `toPrecision()`: A non-standard JavaScript function (supported by some browsers) that allows converting values to a string representation with specified precision and notation (e.g., fixed-point, scientific).

**Special JS Features/Syntax:**

The benchmark uses the following features:

* The use of a variable (`someFloat`) is a basic feature of JavaScript.
* The `toFixed()` and `toPrecision()` functions are part of the standard JavaScript API.

Keep in mind that while these features are widely supported, there may be edge cases or specific browser versions where they behave differently.

**Alternatives:**

If you're looking for alternative methods to round numbers, some options include:

* Using a library like `mathjs` or `decimal.js`, which provide precise arithmetic and rounding functions.
* Utilizing native JavaScript functions from other libraries, such as `big.js` (for large integers) or `core-js` (which includes polyfills for non-standard features).
* Implementing your own custom rounding function using bitwise operations, division, and modulo arithmetic.

It's worth noting that the performance difference between these methods is likely to be negligible in most cases. The benchmark is primarily testing consistency and reliability across different browsers and implementations.

Related benchmarks:

toFixed vs toPrecision vs Math.round() to 1 decimal place (version: 0)

Comparing performance of: toFixed vs toPrecision vs rounding

Created: 4 years ago by: Guest

Jump to the latest result

toFixed

toPrecision

rounding

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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