Benchmark: toFixed vs toPrecision vs Math.round() without string conversion

Script Preparation code:

var someFloat = 0.123456789;

Tests:

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

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark and its test cases.

**Benchmark Definition**

The benchmark is focused on comparing the speed of three different approaches to round a floating-point number without converting it to a string:

1. `toFixed(4)`: This method rounds the number to the specified precision, which in this case is 4 decimal places.
2. `toPrecision(4)`: This method sets the precision of the number to the specified value, which in this case is 4 decimal places.
3. `(Math.round(someFloat*10000)/10000)\r\n`: This approach uses the `Math.round` function to round the number, but first multiplies it by 10,000 and then divides by 10,000.

**Library and Purpose**

None of the test cases use a specific library, as they are built-in JavaScript methods or arithmetic operations.

**Special JS Features/Syntax**

There is no special JavaScript feature or syntax used in these test cases. However, if we were to analyze the `toFixed` and `toPrecision` methods, they utilize the IEEE 754 floating-point standard for decimal representation, which can lead to precision issues with certain inputs.

**Test Cases Comparison**

The three test cases are designed to compare the speed of each approach:

* `toFixed(4)` rounds the number directly to 4 decimal places.
* `toPrecision(4)` sets the precision to 4 decimal places without explicitly rounding.
* `(Math.round(someFloat*10000)/10000)\r\n` uses a workaround to round the number by scaling it and then using `Math.round`.

**Pros and Cons of Each Approach**

1. `toFixed(4)`.
	* Pros: Simple, straightforward approach that rounds the number directly.
	* Cons: May not be suitable for all use cases, as it's designed specifically for rounding numbers to a certain precision.
2. `toPrecision(4)`.
	* Pros: Efficient and fast, as it uses the IEEE 754 standard for decimal representation.
	* Cons: Not explicitly rounds the number; instead, it sets the precision. This might lead to precision issues if the input value is not within the specified range.
3. `(Math.round(someFloat*10000)/10000)\r\n`.
	* Pros: Workaround approach that can be useful when explicit rounding is needed but a direct method is unavailable or too slow.
	* Cons: Scalability issue, as it multiplies and divides the number by large factors (10,000). This approach may not be suitable for very large numbers.

**Other Alternatives**

If you need to round floating-point numbers without converting them to strings, consider using libraries like [Big.js](https://github.com/MicahClay/Big.js) or [Decimal.js](https://matt.mccooey.me decimaljs/), which provide more accurate and efficient rounding methods.

In JavaScript, if you want to round a number to a specific precision without converting it to a string, you can use the following approach:

```javascript
function roundedToPrecision(number, precision) {
  return Number(number.toFixed(precision));
}
```

This implementation uses the `toFixed` method to achieve precise rounding while avoiding string conversion.

Related benchmarks:

toFixed vs toPrecision vs Math.round() without string conversion (version: 0)

Comparison of speed where string/number conversion isn't a factor

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

Created: 6 years ago by: Guest

Jump to the latest result

toFixed(4)

toPrecision(4)

(Math.round(*10000)/10000)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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