Benchmark: Comparaison between foreach with index and foreach without index

Script Preparation code:

var arr = [];
for(var i=0; i < 10000; i++) {
  arr.push(Math.floor(Math.random() * Math.floor(10000)));
}

Tests:

foreach with index
var sum = 0; arr.forEach((e, index) => {sum += arr[index];})
foreach without index
var sum = 0; arr.forEach(e => {sum += e;})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach with index
foreach without index

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
foreach with index	1062.6 Ops/sec
foreach without index	35073.5 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The benchmark is comparing two approaches to iterating over an array in JavaScript: `forEach` with and without indexing.

**Options Compared**

There are only two options being compared:

1. **`forEach` without indexing**: This approach uses the `forEach` method to iterate over the array, but it doesn't provide the index of each element as a parameter.
2. **`forEach` with indexing**: This approach also uses the `forEach` method, but it provides the index of each element as a second argument (`(e, index) => { ... }`).

**Pros and Cons**

* **`forEach` without indexing`**: This approach is simpler to write, as it doesn't require specifying the index. However, it may be slower because the browser has to use other methods (like `length`) to determine the length of the array.
* **`forEach` with indexing`**: This approach provides more control over the iteration process, as you can access the index and element value simultaneously. However, it requires specifying the index in the callback function, which can make the code slightly less readable.

**Other Considerations**

The benchmark is testing how these two approaches perform on a large array of 10,000 random elements. The results will likely depend on factors like:

* Browser performance
* JavaScript engine optimizations
* Array length and data distribution

**Library Usage**

There doesn't appear to be any external libraries being used in this benchmark.

**Special JS Features or Syntax**

The benchmark is using a relatively modern feature: the spread operator (`...`) is not needed, but it's also not present. This might indicate that the test cases were written with a specific JavaScript version in mind (e.g., ES6+).

**Other Alternatives**

If you wanted to write your own benchmarking framework for measuring performance in JavaScript, you could use libraries like:

* `Benchmark.js`: A popular benchmarking library for Node.js and browsers.
* `Benchmarks.net`: A simple, lightweight benchmarking tool specifically designed for web performance testing.

These alternatives can provide more features, flexibility, and accurate results, but they might also require additional setup and configuration.

Related benchmarks:

Comparaison between foreach with index and foreach without index (version: 0)

Comparing performance of: foreach with index vs foreach without index

Created: 2 years ago by: Guest

Jump to the latest result

foreach with index

foreach without index

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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