Benchmark: rest vs arguments

Script Preparation code:

function f(...xs){
  for(let i=0, l=xs.length; i<l; ++i) xs[i];
}
function g(){
  for(let i=0, l=arguments.length; i<l; ++i) arguments[i];
}

Tests:

via rest
f(0,1,2,3,4,5,6,7,8,9)
via arguments
g(0,1,2,3,4,5,6,7,8,9)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
via rest
via arguments

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/117.0

Browser/OS: Firefox 117 on Windows

View result in a separate tab

Test name	Executions per second
via rest	45842920.0 Ops/sec
via arguments	65710808.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**What is being tested?**

The benchmark tests two different ways to iterate over an array of numbers in JavaScript: using the `rest` parameter syntax (introduced in ECMAScript 2015) and the traditional `arguments` object. The test case "via rest" uses the `f` function with the `rest` parameter, while the test case "via arguments" uses the `g` function with the `arguments` object.

**Options compared**

The benchmark compares two options:

1. **Rest parameter syntax (`f` function)**: This is a modern JavaScript feature that allows functions to accept an arbitrary number of parameters using the `...` syntax.
2. **Traditional `arguments` object (`g` function)**: This is a legacy way of accessing function arguments in JavaScript.

**Pros and cons**

* **Rest parameter syntax (`f` function) Pros**:
	+ More concise and expressive code
	+ Easier to read and write
	+ Less prone to errors (e.g., no need to worry about the number of arguments)
* **Rest parameter syntax (`f` function) Cons**:
	+ Only supported in modern browsers and JavaScript engines (not compatible with older versions)
	+ May not work as expected in certain situations (e.g., when used with `apply()` or `bind()`)
* **Traditional `arguments` object (`g` function) Pros**:
	+ Wide browser and JavaScript engine support
	+ More control over iteration (e.g., can use `length` property)
	+ Can work with older versions of JavaScript
* **Traditional `arguments` object (`g` function) Cons**:
	+ Less concise and expressive code
	+ More prone to errors (e.g., need to worry about the number of arguments)

**Library usage**

There is no library explicitly mentioned in the benchmark definition. However, it's worth noting that modern JavaScript engines often use techniques like Just-In-Time (JIT) compilation and caching to optimize function calls. These optimizations may affect the performance results.

**Special JS feature or syntax**

The benchmark does not mention any special JavaScript features or syntax beyond the rest parameter syntax. If you were using a newer feature like `async/await`, `promises`, or ES6 classes, it would be mentioned here.

**Other alternatives**

In this specific case, there are no other alternatives being tested besides the rest parameter syntax and traditional `arguments` object. However, if you wanted to test other iteration methods, such as:

* Using a `for...of` loop
* Using an array method like `forEach()` or `map()`
* Using a library like Lodash's `each()` function

These alternatives would be worth exploring in a different benchmarking context.

Overall, this benchmark provides a clear comparison of two modern JavaScript features and their performance characteristics, helping developers understand the trade-offs between concise code and compatibility with older browsers and JavaScript engines.

Related benchmarks:

rest vs arguments (version: 0)

Comparing performance of: via rest vs via arguments

Created: one year ago by: Guest

Jump to the latest result

via rest

via arguments

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):