Benchmark: Math.trunc vs alts on a positive value

Script Preparation code:

var k = 254 * Math.random() + 1;
var a = -1;

Tests:

Math.trunc
a = Math.trunc(k); a = -1;
Math.floor
a = Math.floor(k); a = -1;
~~
a = ~~k; a = -1;
&-1
a = k & -1; a = -1;
|0
a = k | 0; a = -1;
^0
a = k ^ 0; a = -1;
>>0
a = k >> 0; a = -1;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Math.trunc
Math.floor
~~
&-1
\|0
^0
>>0

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is tested?**

MeasureThat.net is testing various ways to truncate a positive integer value. Truncation is the process of rounding down a number to its nearest whole number, without considering decimal places.

The benchmark is testing six different methods:

1. `Math.trunc()`
2. `Math.floor()`
3. `~~` (bitwise NOT operator)
4. `&-1` (bitwise AND operator with -1)
5. `|0` (bitwise OR operator with 0)
6. `^0` (bitwise XOR operator with 0)
7. `>>0` (right shift operator by 0)

**Options compared**

Each method has its own strengths and weaknesses:

* **Math.trunc()**: This method is specific to the Math library and provides a straightforward way to truncate a number. It's fast but may not be available in older browsers.
* **Math.floor()**: Similar to `Math.trunc()`, but it rounds down to the nearest whole number, which might be more intuitive for some use cases.
* **~~**: This bitwise NOT operator is often used as a shorthand for truncation. However, its behavior can be non-obvious, and it may not work as expected for all types of numbers.
* **&-1** and `|0` and `^0`: These bitwise operators are being used to truncate the number by shifting or masking bits. While they can be faster than traditional Math methods, their behavior is more complex and may require more careful consideration.

**Pros and Cons**

Here's a brief summary of each method:

* **Math.trunc()**:
	+ Pros: Fast, specific to Math library.
	+ Cons: May not be available in older browsers.
* **Math.floor()**:
	+ Pros: More intuitive for some use cases.
	+ Cons: May still round down too far.
* **~~**:
	+ Pros: Simple, fast.
	+ Cons: Non-obvious behavior, may not work for all numbers.
* **&-1**, `|0`, and `^0`:
	+ Pros: Can be faster than traditional Math methods.
	+ Cons: Complex behavior, requires careful consideration.

**Library usage**

The `Math.trunc()` method uses the Math library, which provides various mathematical functions for basic arithmetic operations. The Math library is widely supported across most browsers.

**Special JS feature or syntax**

None of the test cases use any special JavaScript features or syntax that would require a deep understanding of the language.

**Alternatives**

If you need to perform truncation in your own code, here are some alternatives:

* Use `Math.trunc()` if it's available and suitable for your use case.
* Implement a custom truncation function using bitwise operators (`&-1`, `|0`, `^0`), but be aware of their complex behavior.
* Consider using alternative libraries or polyfills that provide a more robust truncation function.

Keep in mind that the best approach will depend on the specific requirements and constraints of your project.

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/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Windows

View result in a separate tab

Test name	Executions per second
Math.trunc	3336284.8 Ops/sec
Math.floor	2878060.8 Ops/sec
~~	4637446.0 Ops/sec
&-1	4938558.5 Ops/sec
\|0	5080067.0 Ops/sec
^0	5065015.5 Ops/sec
>>0	4975457.0 Ops/sec

Related benchmarks:

Math.trunc vs alts on a positive value (version: 0)

Comparing performance of: Math.trunc vs Math.floor vs ~~ vs &-1 vs |0 vs ^0 vs >>0

Created: one year ago by: Guest

Jump to the latest result

Math.trunc

Math.floor

~~

&-1

|0

^0

>>0

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):