Benchmark: for (cached length) vs foreach vs some

Script Preparation code:

var array = new Array(100);

Tests:

for
const len = array.length; for (var i = 0; i < len; i++) { array[i]; }
foreach
array.forEach(function(item, index) { return item; });
some
array.some(function(item, index) { return item === array[index]; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 20 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Edg/131.0.0.0

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
for	940015.4 Ops/sec
foreach	5576875.5 Ops/sec
some	5237095.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into explaining the provided benchmark.

The benchmark is designed to compare the performance of three different loop constructs in JavaScript: `for`, `forEach`, and `some`.

**Loop Constructs Comparison**

1. **For Loop**: This is a traditional loop construct that uses an index variable to iterate over an array.
```javascript
const len = array.length;
for (var i = 0; i < len; i++) {
  array[i];
}
```
Pros:

* Simple and straightforward to implement.
* Can be optimized for certain use cases.

Cons:

* May not perform well if the loop has many iterations, as it involves incrementing the index variable.

2. **ForEach Loop**: This is a modern loop construct that uses an iterator function to iterate over an array.
```javascript
array.forEach(function(item, index) {
  return item;
});
```
Pros:

* Simplifies the loop logic and eliminates the need for manual indexing.
* Can be more efficient in some cases.

Cons:

* May not perform well if the loop has many iterations or involves complex logic.

3. **Some Loop**: This is a variant of the `forEach` loop that returns `true` if at least one element passes the test, and `false` otherwise.
```javascript
array.some(function(item, index) {
  return item === array[index];
});
```
Pros:

* Can be more efficient than `forEach` if only one iteration is needed.

Cons:

* May not perform well if the loop has many iterations or involves complex logic.

**Library Used: None**

There are no libraries used in this benchmark. The loops are implemented using native JavaScript syntax.

**Special JS Features/ Syntax: None**

There are no special features or syntax used in this benchmark that would require a deep understanding of JavaScript.

**Other Alternatives**

In addition to the three loop constructs mentioned, other alternatives could include:

* `while` loop
* `do-while` loop
* Array methods like `map`, `filter`, and `reduce`

These alternatives may offer different trade-offs in terms of performance, readability, and complexity.

To prepare for this benchmark, one would typically need to write test cases that implement each of the three loops and execute them on a given array size. The test cases would then be run multiple times with varying execution counts to obtain a rough estimate of their relative performance.

Related benchmarks:

for (cached length) vs foreach vs some (version: 0)

Compare loop performance

Comparing performance of: for vs foreach vs some

Created: 6 years ago by: Guest

Jump to the latest result

for

foreach

some

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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