Benchmark: for vs foreach vs some vs for..of

Script Preparation code:

var array = new Array(100);

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: 7 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/147.0.0.0 Safari/537.36

Browser/OS: Chrome 147 on Windows

View result in a separate tab

Test name	Executions per second
for	5255050.0 Ops/sec
foreach	9258324.0 Ops/sec
some	8399615.0 Ops/sec
for..of	1189778.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**What is being tested:**
The provided benchmark tests the performance of four different loop constructs in JavaScript:

1. Traditional `for` loop
2. `forEach` method
3. `some` method
4. `for...of` loop (introduced in ECMAScript 2015)

These loops are used to iterate over an array and perform some operation on each element.

**Options compared:**

* **Traditional `for` loop**: This is the most common way of looping in JavaScript. It uses a manual index variable and increment/decrement operations.
* **`forEach` method**: Introduced in ECMAScript 2009, this method allows you to iterate over an array without exposing the index variable to the caller.
* **`some` method**: Also introduced in ECMAScript 2009, this method returns `true` if at least one element of the array passes a test provided as a function.
* **`for...of` loop**: Introduced in ECMAScript 2015, this loop is specifically designed for iterating over arrays and other iterable objects.

**Pros and cons:**

* **Traditional `for` loop**:
	+ Pros: More control over the iteration process, no overhead of method calls or additional function parameters.
	+ Cons: Can be error-prone if not implemented correctly, more verbose.
* **`forEach` method**:
	+ Pros: Less error-prone than traditional loops, provides a clear interface for iterating over arrays.
	+ Cons: Creates an object on the heap, which can lead to memory allocation issues in some browsers.
* **`some` method**:
	+ Pros: Can stop iterating as soon as it finds a matching element, reducing overhead.
	+ Cons: May not be suitable for all use cases, as it only returns `true` if at least one element passes the test.
* **`for...of` loop**:
	+ Pros: Designed specifically for iterating over arrays and other iterable objects, provides a concise way to write loops.
	+ Cons: Less flexible than traditional `for` loops or `forEach`, may not work with non-array iterables.

**Library usage:**
None of the provided benchmark cases use any external libraries.

**Special JavaScript feature/syntax:**
The `for...of` loop was introduced in ECMAScript 2015, which is a relatively recent syntax. This means that older browsers and versions of JavaScript may not support this syntax.

**Benchmark preparation code:**
The script prepares an array with 100 elements using the line `var array = new Array(100);`.

In summary, this benchmark tests the performance of four different loop constructs in JavaScript, providing a clear comparison of their execution times. The results can be useful for developers to choose the most suitable loop construct for their specific use cases, taking into account factors like memory allocation and iteration overhead.

Related benchmarks:

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

Compare loop performance

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

Created: 9 years ago by: Guest

Jump to the latest result

for

foreach

some

for..of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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