Benchmark: toFixed vs toPrecision vs Math.round() Number Type

Script Preparation code:

var someFloat = 0.123456789;

Tests:

toFixed(4)
+someFloat.toFixed(4);
toPrecision(4).toString()
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: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.141 Safari/537.36

Browser/OS: Chrome 87 on Windows

View result in a separate tab

Test name	Executions per second
toFixed(4)	1691188.4 Ops/sec
toPrecision(4).toString()	2585890.2 Ops/sec
(Math.round(*10000)/10000).toString()	3126316.2 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll explain the benchmark in detail, covering what's tested, compared options, pros and cons, and other considerations.

**Benchmark Definition**

The benchmark measures the performance of three different approaches for converting a floating-point number to a string with a specific precision: `toFixed`, `toPrecision`, and `Math.round()` combined with division by a large factor. The test focuses on the JavaScript engine's ability to perform these conversions efficiently, likely to assess optimization or caching behavior.

**Options Compared**

1. **`toFixed(4)`**: Converts the float to a string with 4 decimal places using the `toFixed()` method.
2. **`toPrecision(4).toString()`**: Converts the float to a string with 4 precision units (equivalent to 6 significant figures) using the `toPrecision()` method and then converts the resulting string to a number using `toString()`.
3. **`(Math.round(*10000)/10000).toString()`**: Rounds the float to an integer by multiplying it by 10,000, rounding, and then dividing by 10,000 before converting the result to a string.

**Pros and Cons**

1. **`toFixed(4)`**:
	* Pros: Simple, straightforward conversion.
	* Cons: May involve some overhead due to method call and argument passing.
2. **`toPrecision(4).toString()`**:
	* Pros: More precise control over precision units.
	* Cons: Introduces an extra step (converting the result back to a string) and may incur additional overhead.
3. **`(Math.round(*10000)/10000).toString()`**:
	* Pros: Avoids method calls and argument passing, potentially reducing overhead.
	* Cons: Involves arithmetic operations with large factors, which can be computationally expensive.

**Other Considerations**

The benchmark might also test the JavaScript engine's handling of different data types (e.g., integers, floats) or explore variations in input values (e.g., very large or very small numbers).

**Libraries and Special JS Features**

None are explicitly mentioned in the provided benchmark definition. However, it's worth noting that `toFixed()` and `toPrecision()` rely on the Number object's behavior.

**Alternatives**

If you want to explore alternative approaches for converting floating-point numbers to strings with precision, consider:

1. **Using a library**: The `decimal.js` library can help with precise arithmetic operations and formatting.
2. **Implementing a custom conversion**: You could write your own implementation using bitwise operations or other methods to achieve the desired precision.
3. **Using a different data type**: If possible, converting to integers (using rounding) might be more efficient than working with floating-point numbers.

Keep in mind that these alternatives might not be directly comparable to the original benchmark, as they may introduce new factors or assumptions about the JavaScript engine's behavior.

Related benchmarks:

toFixed vs toPrecision vs Math.round() Number Type (version: 0)

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

Created: 3 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):