Benchmark: Comparaison between foreach with index and foreach without index and same treatment

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 += e;})
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 (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
foreach with index	56327.3 Ops/sec
foreach without index	55942.2 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the JavaScript microbenchmark on MeasureThat.net.

**Benchmark Definition**

The benchmark compares two approaches for iterating over an array: using `forEach` with an index parameter (`(e, index) => { ... }`) and without an index parameter (`e => { ... }`). The test creates a large array of random integers and then iterates over it twice using each approach, summing up the elements in both cases.

**Options Compared**

The two options being compared are:

1. `forEach` with an index parameter: `(e, index) => { sum += e; }`
	* This approach allows access to the current element (`e`) and its index in the array.
	* Pros:
		+ Allows for more flexible iteration, as it's possible to use the index to perform additional operations or conditional statements.
	* Cons:
		+ Requires passing an extra parameter (the index) to the callback function.
2. `forEach` without an index parameter: `e => { sum += e; }`
	* This approach only passes the current element (`e`) to the callback function, without providing any additional context (like its index).
	* Pros:
		+ Slightly more concise and easier to read.
	* Cons:
		+ Less flexible than the first approach, as it doesn't provide access to the index.

**Pros and Cons**

The choice between these two approaches depends on the specific use case. If you need to perform operations that rely on the index of each element (e.g., iterating over an array and performing actions based on its position), using `forEach` with an index parameter is a good choice. However, if you're only concerned with summing up elements without any additional processing required by their indices, using `forEach` without an index parameter might be more efficient.

**Library Usage**

There is no explicit library mentioned in the benchmark definition or individual test cases. The `forEach` method is a built-in JavaScript function that iterates over arrays and executes a callback function for each element.

**Special JS Feature/Syntax**

There is no specific JavaScript feature or syntax being tested in this benchmark. It's purely focused on comparing two iteration approaches using standard JavaScript.

**Alternatives**

If you're interested in exploring alternative ways to iterate over arrays, here are a few options:

1. `for...of` loop: This is a more modern and concise way of iterating over arrays, which doesn't require explicit index management.
2. `map()`, `filter()`, or `reduce()` methods: These are array operations that can be used to transform, filter, or reduce the size of an array, respectively.
3. Iterators and iterators-based APIs (e.g., `Array.prototype.entries()`: These allow for more fine-grained control over iteration and manipulation of arrays.

Keep in mind that these alternatives might have different performance characteristics depending on the specific use case and implementation details.

Related benchmarks:

Comparaison between foreach with index and foreach without index and same treatment (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):