Benchmark: toFixed vs toPrecision vs Math.round() vs Math.floorfast2

Script Preparation code:

var someFloat = 673.123456789;

Tests:

toFixed(4)
someFloat.toFixed(4);
toPrecision(4).toString()
someFloat.toPrecision(4);
(Math.round(*10000)/10000).toString()
(Math.round(someFloat*10000)/10000);
Math.floor fast
~~(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()
Math.floor fast

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/96.0.4664.110 Safari/537.36

Browser/OS: Chrome 96 on Windows

View result in a separate tab

Test name	Executions per second
toFixed(4)	3669810.8 Ops/sec
toPrecision(4).toString()	3839167.0 Ops/sec
(Math.round(*10000)/10000).toString()	3404421.8 Ops/sec
Math.floor fast	8661514.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation.

**Benchmark Context**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. A benchmark is a controlled experiment designed to measure the performance of a specific piece of code or functionality. In this case, we have a benchmark that compares the performance of four different methods for rounding a floating-point number: `toFixed`, `toPrecision`, `Math.round()`, and an alternative implementation using bitwise operations (`~~`).

**Options Compared**

The four options are compared in terms of their execution time:

1. **`toFixed(4)`**: Rounds the number to 4 decimal places.
2. **`toPrecision(4).toString()`**: Rounds the number to 4 significant digits and converts it to a string using `toString()`.
3. **`(Math.round(someFloat*10000)/10000).toString()`**: Rounds the number by multiplying it by 10,000, rounding to the nearest integer using `Math.round()`, and then dividing by 10,000.
4. **`~~(someFloat * 10000) / 10000`**: Rounds the number using bitwise operations (`~~`). The `~~` operator performs a two's complement round (i.e., rounds down if the fractional part is greater than or equal to 0.5).

**Pros and Cons**

Here's a brief summary of the pros and cons of each option:

1. **`toFixed(4)`**: Pros:
	* Simple and intuitive.
	* Fast execution time.
Cons:
	* May not produce precise results due to rounding errors.
2. **`toPrecision(4).toString()`**:
	* Pros:
		+ Produces more accurate results than `toFixed`.
		+ Can be useful when working with scientific notation or significant digits.
	* Cons:
		+ Slower execution time compared to `toFixed`.
		+ Requires calling `toString()` to get the result as a string.
3. **`(Math.round(someFloat*10000)/10000).toString()`**:
	* Pros:
		+ More accurate than `toFixed` and can be used for more precise rounding.
		+ Can be useful when working with large numbers or high-precision arithmetic.
	* Cons:
		+ Requires multiplying and dividing by large numbers, which can lead to precision errors.
		+ More complex implementation compared to `toFixed`.
4. **`~~(someFloat * 10000) / 10000`**:
	* Pros:
		+ Fast execution time due to bitwise operations.
		+ Simple implementation.
Cons:
	* May not produce accurate results due to the use of two's complement rounding.
	* Limited precision and control over the rounding behavior.

**Library Usage**

In this benchmark, we don't see any explicit library usage. However, it's worth noting that `Math.round()` is a built-in JavaScript function that uses a specialized algorithm for rounding numbers.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax used in this benchmark. The code is straightforward and relies on standard JavaScript operators and functions.

**Other Alternatives**

If you're interested in exploring alternative rounding methods, here are some options:

1. **`Number.EPSA`**: Some browsers have a `Number.EPSA` constant that can be used to specify the number of decimal places for `toFixed()`.
2. **`Big.js` or `decimal.js` libraries**: These libraries provide more precise arithmetic operations and rounding functions, but may introduce additional overhead due to their complexity.
3. **Custom implementation using IEEE 754 floating-point numbers**: You can implement your own rounding algorithms using the IEEE 754 standard for floating-point numbers.

Keep in mind that these alternatives may not be as simple or intuitive as the methods used in this benchmark, and may require more expertise in low-level programming or numerical computations.

Related benchmarks:

toFixed vs toPrecision vs Math.round() vs Math.floorfast2 (version: 0)

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

Created: 3 years ago by: Guest

Jump to the latest result

toFixed(4)

toPrecision(4).toString()

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

Math.floor fast

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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