Benchmark: Array loop vs safe foreach

Script Preparation code:

var arr = [],
LoopFunctionHandle = { halt: false };

for (var i = 0; i < 1000; i++) {
  arr[i] = i;
}
  
function someFn(i) {
  return i * 3 * 8;
}

Tests:

foreach
arr.forEach(function (item) { if (!LoopFunctionHandle.halt) { someFn(item); } });
for
for (var i = 0, len = arr.length; i < len; i++) { someFn(arr[i]); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
foreach
for

Fastest: N/A

Slowest: N/A

Latest run results:

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

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

**Benchmark Definition**

The benchmark definition is a JSON object that describes the test case. It contains two main parts:

1. **Script Preparation Code**: This code sets up the environment for the benchmark. In this case, it creates an empty array `arr` and defines a function `someFn` that takes an integer as input and returns its triple multiplied by 8.
2. **Html Preparation Code**: This is not used in this benchmark definition.

The script preparation code is executed before running the test cases.

**Test Cases**

There are two test cases:

1. **"foreach"`**
	* The benchmark definition uses the `forEach` method to iterate over the array `arr`. It calls the function `someFn` for each item in the array, but only if a special variable `LoopFunctionHandle.halt` is set to `false`.
2. **"for"`**
	* This test case uses a traditional `for` loop to iterate over the array `arr`. The loop iterates from 0 to the length of the array, and for each iteration, it calls the function `someFn` with the current element as input.

**Options Compared**

The two test cases compare the performance of using the `forEach` method versus a traditional `for` loop to iterate over an array.

**Pros and Cons**

* **"foreach"`:
	+ Pros:
		- More concise and readable code
		- Less prone to off-by-one errors or indexing issues
	+ Cons:
		- Can be slower due to the overhead of the iterator object
		- May not perform as well for large datasets
* **"for"`:
	+ Pros:
		- Typically faster due to direct access to the array elements
		- More control over loop iterations and error handling
	+ Cons:
		- Longer and more verbose code can lead to errors or off-by-one issues

**Library**

There is no specific library used in this benchmark definition.

**Special JS Features/Syntax**

None mentioned.

Now, let's look at the benchmark results:

The latest benchmark result shows the performance metrics for each test case. The key values are:

* **ExecutionsPerSecond**: The number of iterations performed by each test case per second.
* **TestName**: The name of the test case being reported.

In this case, the "for" loop test case performs approximately 4500 executions per second on Chrome 95 on a Desktop with Windows operating system. The "foreach" loop test case performs around 5771 executions per second under the same conditions.

**Alternatives**

If you're looking for alternative ways to compare performance or optimize array iteration, here are some options:

* Using `map()` and `reduce()` methods instead of `forEach` or `for` loops.
* Utilizing Web Workers or parallel processing to iterate over large datasets.
* Implementing custom iteration logic using techniques like bit manipulation or binary search.

Keep in mind that the best approach will depend on your specific use case, dataset size, and performance requirements.

Related benchmarks:

Array loop vs safe foreach (version: 0)

Comparing performance of: foreach vs for

Created: 4 years ago by: Registered User

Jump to the latest result

foreach

for

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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