Benchmark: for vs foreach vs some vs for..of (fixed)

Script Preparation code:

var array = [...new Array(1000)];

Tests:

for
for (var i = 0; i < array.length; i++) { array[i]; }
foreach
array.forEach(function(i) { array[i]; });
some
array.some(function(i) { array[i]; });
for..of
for (var i of array) { array[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some
for..of

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4251.0 Safari/537.36

Browser/OS: Chrome 87 on Windows

View result in a separate tab

Test name	Executions per second
for	2457.3 Ops/sec
foreach	4066.0 Ops/sec
some	3974.2 Ops/sec
for..of	4411.7 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the provided benchmark definition and test cases.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmarking tool called MeasureThat.net. The benchmark compares the performance of four different loop types:

1. Traditional `for` loop
2. `forEach` loop (array iteration)
3. `some` loop (array iteration with early exit)
4. `for..of` loop (array iteration with automatic index)

The benchmark uses a fixed array size of 1000 elements, which is pre-created using the "Script Preparation Code".

**Loop Options Compared**

Here's a brief overview of each loop option:

* **Traditional `for` loop**: This is the most basic type of loop. It uses an incrementing index variable to access array elements.
	+ Pros: Simple and well-supported by most browsers.
	+ Cons: Can be slower due to the need to manually increment the index variable.
* **`forEach` loop (array iteration)**: Introduced in ECMAScript 2015, this loop type is designed for iterating over arrays. It uses a callback function to process each element.
	+ Pros: More efficient than traditional `for` loops, as it avoids manual indexing and incrementing.
	+ Cons: Requires modern browsers that support the `forEach` method.
* **`some` loop (array iteration with early exit)**: Another ECMAScript 2015 feature, this loop type is similar to `forEach`, but returns a boolean value indicating whether any element passed the condition.
	+ Pros: More efficient than traditional `for` loops for large arrays, as it can stop iterating early if no elements match the condition.
	+ Cons: Requires modern browsers that support the `some` method.
* **`for..of` loop (array iteration with automatic index)**: Introduced in ECMAScript 2015, this loop type is designed for iterating over arrays. It uses an iterator object to access array elements and automatically increments the index variable.
	+ Pros: Most efficient of all loop types, as it minimizes manual indexing and incrementing.
	+ Cons: Requires modern browsers that support the `for..of` syntax.

**Library Used**

The benchmark uses no external libraries. It relies solely on built-in JavaScript features to execute the loops.

**Special JS Features or Syntax**

The benchmark uses several ES2015/ES2017 features, including:

* `forEach`: Introduced in ECMAScript 2015.
* `some`: Introduced in ECMAScript 2015.
* `for..of`: Introduced in ECMAScript 2015.

These features are widely supported by modern browsers and are a good indication of the benchmark's compatibility with current JavaScript versions.

**Other Alternatives**

If the `for`, `forEach`, or `some` loops were not available, alternative loop types could have been used. Some examples include:

* Traditional `while` loop: A more low-level approach that requires manual indexing and incrementing.
* Recursive functions: An approach where a function calls itself to iterate over array elements.

However, these alternatives would likely incur additional overhead due to the need for manual indexing and incrementing, making them less efficient than the compared loop types.

Related benchmarks:

for vs foreach vs some vs for..of (fixed) (version: 0)

Compare loop performance

Comparing performance of: for vs foreach vs some vs for..of

Created: 4 years ago by: Guest

Jump to the latest result

for

foreach

some

for..of

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):