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

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]; }
for...of with entries
for (const [i, value] of array.entries()) { array[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
some
for..of
for...of with entries

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

The provided JSON represents a JavaScript benchmarking test, where users can compare the performance of different loop constructs in JavaScript.

**What is tested?**

The benchmark tests four different loop constructs:

1. `for` loop: A traditional loop using a counter variable (`i`) to iterate over an array.
2. `forEach` loop: An iteration method provided by the Array prototype, which iterates over an array and executes a callback function for each element.
3. `some` loop: A method that returns `true` if at least one element in the array satisfies the condition specified as a callback function.
4. `for..of` loop with and without `entries`: Two variants of the `for...of` loop, which iterate over an array using a more modern approach. The first variant uses the spread operator (`...`) to create an iterator from the array's `entries()` method. The second variant uses the `entries()` method directly.

**Options compared**

The benchmark compares the performance of these four loop constructs under different conditions:

* Number of executions per second
* Device platform (Desktop)
* Browser (Chrome 126)

**Pros and Cons of each approach:**

1. **`for` loop**:
	* Pros: Simple, easy to understand, widely supported.
	* Cons: Can be slow due to the overhead of incrementing a counter variable.
2. **`forEach` loop**:
	* Pros: Modern, concise syntax, efficient for small arrays.
	* Cons: May have performance issues with large arrays, as it relies on the Array prototype's iteration mechanism.
3. **`some` loop**:
	* Pros: Fast and efficient for checking conditions on individual elements.
	* Cons: Not suitable for iterating over arrays element-by-element; its purpose is to check a condition on each element.
4. **`for..of` loop with `entries`**:
	* Pros: Modern, concise syntax, efficient for large arrays using the spread operator and `entries()` method.
	* Cons: May have compatibility issues with older browsers or versions of Node.js.

The benchmark results show that:

* The `forEach` loop is the fastest among all options tested.
* The `some` loop is also relatively fast but slower than the `for..of` loops.
* The `for..of` loop with and without `entries` are comparable in performance, with slight differences between them.

**Other considerations:**

* Library usage: None of these loop constructs rely on external libraries or frameworks. However, some browsers (like Chrome) may use internal optimizations or caching that affect performance.
* Special JavaScript features/syntax: None mentioned in the provided JSON.

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Linux

View result in a separate tab

Test name	Executions per second
for	128213.6 Ops/sec
foreach	7029449.5 Ops/sec
some	6878393.0 Ops/sec
for..of	209116.5 Ops/sec
for...of with entries	206435.8 Ops/sec

Related benchmarks:

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

Compare loop performance

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

Created: 4 months ago by: Guest

Jump to the latest result

for

foreach

some

for..of

for...of with entries

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):