Benchmark: toFixed vs Math.round() 2

Script Preparation code:

var someFloat = 0.123456789;

Tests:

+toFixed(2)
+someFloat.toFixed(2);
Math.round(*100)/100
Math.round(someFloat*100)/100;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
+toFixed(2)
Math.round(*100)/100

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
+toFixed(2)	9283837.0 Ops/sec
Math.round(*100)/100	11252669.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**What is tested?**

The benchmark tests two ways to round a floating-point number: `toFixed()` and `Math.round()`. The goal is to determine which method is faster for rounding numbers with 2 decimal places.

**Options compared:**

There are two options being compared:

1. **`toFixed(2)`**: This method converts the floating-point number to a string, padding it with zeros if necessary, and then converts the resulting string back to a float. The second argument `2` specifies the minimum number of digits to be included in the formatted string.
2. **`Math.round(*100)/100`**: This method first multiplies the floating-point number by 100 to shift its decimal point two places to the right, then rounds it using `Math.round()`, and finally divides the result by 100 to restore the original decimal point.

**Pros and cons of each approach:**

1. **`toFixed(2)`**:
	* Pros:
		+ More readable code (less magic numbers)
		+ May be more intuitive for developers familiar with string formatting
	* Cons:
		+ Requires creating a string, which can be slower than arithmetic operations
		+ May not work well with very large or very small numbers due to precision issues
2. **`Math.round(*100)/100`**:
	* Pros:
		+ Faster, as it only involves arithmetic operations
		+ More robust, as it doesn't require creating a string
	* Cons:
		+ Less readable code (more magic numbers)
		+ May not be immediately obvious what's happening in the calculation

**Library and special JS feature:**

There are no libraries used in this benchmark. However, the `Math.round()` function is a built-in JavaScript method.

**Special JS feature:**

There is no specific JavaScript feature being tested or leveraged in this benchmark.

**Other alternatives:**

If you want to explore alternative methods for rounding numbers, some options include:

1. **`Number.toFixed(2)`**: This is similar to `toFixed(2)`, but uses a different syntax.
2. **`BigInt`**: For very large or very small numbers, using `BigInt` and `toString()` with a specific radix (e.g., 16 for hexadecimal) might be faster or more efficient.
3. **Third-party libraries**: There are many third-party libraries available that provide optimized rounding functions, such as `lodash.round()`, but these would likely incur performance overhead.

Keep in mind that the choice of rounding method depends on the specific use case and requirements of your project.

Related benchmarks:

toFixed vs Math.round() 2 (version: 0)

Comparing performance of: +toFixed(2) vs Math.round(*100)/100

Created: 4 years ago by: Guest

Jump to the latest result

+toFixed(2)

Math.round(*100)/100

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):