Benchmark: javascript loops small

Tests:

foreach
const items = Array.from({length: 10}, () => Math.floor(Math.random() * 40)); let index = 0; items.forEach(i => index++);
for-in
const items = Array.from({length: 10}, () => Math.floor(Math.random() * 40)); let index = 0; for (let i in items) { index++; }
for-of
const items = Array.from({length: 10}, () => Math.floor(Math.random() * 40)); let index = 0; for (let i of items) { index++; }
for
const items = Array.from({length: 10}, () => Math.floor(Math.random() * 40)); let index = 0; for(let i = 0; i < items.length; ++i) { index++; }
optimized-for
const items = Array.from({length: 10}, () => Math.floor(Math.random() * 40)); let index = 0; for(let i = items.length; i > 0; --i) { index++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for-in
for-of
for
optimized-for

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The benchmark definition is provided in JSON format, which describes the test scenario. In this case, it's a simple loop that iterates over an array of numbers. The script preparation code is empty, indicating that no specific setup or initialization is required for the benchmark.

Here's what's being tested:

* An array of 10 random integers between 0 and 39 is created using `Array.from()`.
* A variable `index` is initialized to 0.
* Four different loop constructs are used to iterate over the array: `foreach`, `for-in`, `for-of`, and a custom "optimized-for" loop.

**Loop Options**

Let's examine each loop option:

1. **`foreach`**: This loop uses the `forEach()` method, which iterates over the array elements using a callback function.
	* Pros: Simple and concise syntax. Easy to read and write.
	* Cons: May incur overhead due to function call overhead and potential cache thrashing.
2. **`for-in`**: This loop uses the `in` operator to iterate over the array properties (i.e., indices).
	* Pros: Can be used for non-array data structures, but may not provide accurate results for arrays.
	* Cons: May be slower due to the need to check the property existence and potential cache thrashing.
3. **`for-of`**: This loop uses the `for...of` statement, which iterates over the array elements using a simple iterator syntax.
	* Pros: Efficient and modern syntax. Easy to read and write.
	* Cons: May be slower for older browsers or JavaScript engines that don't support this syntax.
4. **Custom "optimized-for" loop**: This loop uses a traditional `for` loop with indexing, which is often considered the most efficient way to iterate over arrays.
	* Pros: Can be optimized for specific hardware or CPU architectures.
	* Cons: May require more boilerplate code and is less readable than other options.

**Browser-Specific Considerations**

The benchmark results are provided for a specific Firefox 48 browser on a Mac OS X 10.6 desktop platform. The results may not be representative of other browsers, platforms, or JavaScript engines.

**Skip Preambles**

As you mentioned, we'll skip the preamble and dive into the test cases.

Let's take a closer look at each test case:

1. `foreach`
2. `for-in`
3. `for-of`
4. `for`

Each of these tests iterates over the same array, but using different loop constructs. The results will help determine which loop construct is most efficient in this specific scenario.

**Other Alternatives**

If you're interested in exploring alternative approaches, here are a few:

1. **`Array.prototype.map()`**: Instead of using a loop to iterate over an array, you can use the `map()` method to create a new array with transformed elements.
2. **`Promise.all()`**: If your test involves asynchronous operations or callbacks, you may want to consider using `Promise.all()` to parallelize the execution.
3. **Just-In-Time (JIT) Compilation**: Some JavaScript engines, like V8 in Chrome, use JIT compilation to optimize performance-critical code.

Keep in mind that these alternatives may not be suitable for every benchmarking scenario and may require more complex setup or modifications to your test case.

If you have any specific questions about the benchmark results or would like to explore alternative approaches, feel free to ask!

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:48.0) Gecko/20100101 Firefox/48.0

Browser/OS: Firefox 48 on Mac OS X 10.6

View result in a separate tab

Test name	Executions per second
foreach	157075.2 Ops/sec
for-in	88800.1 Ops/sec
for-of	160777.2 Ops/sec
for	198278.4 Ops/sec
optimized-for	212082.1 Ops/sec

Related benchmarks:

javascript loops small (version: 0)

Comparing performance of: foreach vs for-in vs for-of vs for vs optimized-for

Created: one year ago by: Guest

Jump to the latest result

foreach

for-in

for-of

for

optimized-for

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):