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]; }

Historical Performance Data aggregated from 576 community runs

Desktop Results:

Chrome 408 runs

foreach

5.4M/s

some

5.2M/s

for..of

262K/s

for

162K/s

Fastest: foreach (33.6x faster)

View exact numbers

✓ foreach: 5,440,988 ops/sec
• some: 5,218,737 ops/sec
• for..of: 262,374 ops/sec
• for: 162,142 ops/sec

Firefox 104 runs

for

20.4M/s

some

11.8M/s

foreach

8.9M/s

for..of

1.5M/s

Fastest: for (14.0x faster)

View exact numbers

✓ for: 20,354,768 ops/sec
• some: 11,780,772 ops/sec
• foreach: 8,885,647 ops/sec
• for..of: 1,451,799 ops/sec

Safari 23 runs

some

683K/s

foreach

645K/s

for..of

258K/s

for

257K/s

Fastest: some (2.7x faster)

View exact numbers

✓ some: 682,532 ops/sec
• foreach: 644,910 ops/sec
• for..of: 257,879 ops/sec
• for: 256,623 ops/sec

Other 6 runs

foreach

4.3M/s

some

4.3M/s

for..of

215K/s

for

138K/s

Fastest: foreach (31.6x faster)

View exact numbers

✓ foreach: 4,345,528 ops/sec
• some: 4,301,035 ops/sec
• for..of: 215,145 ops/sec
• for: 137,643 ops/sec

Mobile Results:

Chrome 27 runs

foreach

3.1M/s

some

2.9M/s

for..of

142K/s

for

95K/s

Fastest: foreach (32.9x faster)

View exact numbers

✓ foreach: 3,122,205 ops/sec
• some: 2,889,788 ops/sec
• for..of: 142,178 ops/sec
• for: 94,819 ops/sec

Safari 8 runs

foreach

699K/s

some

687K/s

for..of

213K/s

for

200K/s

Fastest: foreach (3.5x faster)

View exact numbers

✓ foreach: 698,990 ops/sec
• some: 686,903 ops/sec
• for..of: 212,950 ops/sec
• for: 199,802 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

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: 3 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/150.0.0.0 Safari/537.36

Browser/OS: Chrome 150 on Mac OS X 10.15.7

View result in a separate tab

foreach

6.5M/s

some

6.4M/s

for

4.0M/s

for..of

707K/s

View exact numbers

Test name	Executions per second
✓ foreach	6,459,088 Ops/sec
some	6,388,482 Ops/sec
for	3,950,967 Ops/sec
for..of	706,916 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.

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

Go to the latest result

for

foreach

some

for..of

Historical Performance Data aggregated from 576 community runs

Desktop Results:

Chrome 408 runs

Firefox 104 runs

Safari 23 runs

Other 6 runs

Mobile Results:

Chrome 27 runs

Safari 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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

Go to the latest result

for

foreach

some

for..of

Historical Performance Data aggregated from 576 community runs

Desktop Results:

Chrome 408 runs

Firefox 104 runs

Safari 23 runs

Other 6 runs

Mobile Results:

Chrome 27 runs

Safari 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

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