Benchmark: for vs const for..of

Script Preparation code:

var array = new Array(100);
var array2 = [];

Tests:

for
for (var i = 0; i < array.length; i++) { array2.push(array[i]); }
for ... of
for (const item of array) { array2.push(item); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
for ... of

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmarking scenario and explain what's being tested.

**Benchmark Overview**

The benchmark is designed to compare the performance of two different loop constructs in JavaScript: traditional `for` loops and the new `for...of` syntax. The goal is to determine which approach is faster for a specific task.

**Loop Constructs Comparison**

In the provided benchmark, we have two test cases:

1. **Traditional `for` loop**: This loop uses the `var` keyword to declare the loop variable `i`, and it iterates over an array using the `length` property.
2. **`for...of` loop**: This loop uses the `const` keyword to declare the loop variable `item`, and it iterates over an array using the `of` clause.

**Options Compared**

The benchmark is comparing the performance of these two loop constructs:

Pros of traditional `for` loops:

* Wide support across older browsers and versions
* Well-established syntax
* Easy to understand for developers familiar with C-style looping

Cons of traditional `for` loops:

* Can lead to memory leaks due to variable scope issues (e.g., using `var i`)
* May not provide the same level of safety as modern loop constructs

Pros of `for...of` loops:

* More concise and expressive syntax
* Built-in support for iterating over arrays, objects, and other iterables
* Improved performance compared to traditional `for` loops (as demonstrated by the benchmark)

Cons of `for...of` loops:

* May not be supported in older browsers or versions
* Can be less familiar to developers without experience with modern JavaScript features

**Library Used**

In this benchmark, there is no explicit library being used. However, it's essential to note that some libraries (e.g., jQuery) might provide similar functionality to the `for...of` loop.

**Special JS Feature or Syntax**

The `for...of` loop uses a new syntax introduced in ECMAScript 2015 (ES6). This feature allows developers to iterate over arrays and other iterables using a concise syntax, making it easier to write readable and maintainable code. The benchmark is testing the performance of this feature.

**Other Alternatives**

If you're interested in exploring alternative loop constructs or optimizing your JavaScript code for better performance, here are some options:

* **Array.prototype.forEach()**: This method provides a more functional programming approach to iterating over arrays.
* **Set and Map data structures**: These collections can be used for faster lookups and manipulation of data.
* **WebAssembly (WASM)**: This binary format allows you to compile languages like C++ or Rust for execution in web browsers, potentially leading to improved performance.

Keep in mind that the choice of loop construct, library, or alternative approach depends on your specific use case, target audience, and desired outcome.

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 114 on Android

View result in a separate tab

Test name	Executions per second
for	10013.4 Ops/sec
for ... of	26863.9 Ops/sec

Related benchmarks:

for vs const for..of (version: 0)

Compare loop performance

Comparing performance of: for vs for ... of

Created: one year ago by: Guest

Jump to the latest result

for

for ... of

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 29 days ago):